Follow-up to #393 : the embedded-JPEG scan shares a work budget

scan_for_jpeg walks every JPEG-like start in a container it can't parse; each walk runs through the marker segments that follow (up to 4096) and their entropy data. A crafted CRW/MRW/X3F (or unsupported TIFF raw) of fake starts one after another makes every walk cover most of the file: quadratic, about a minute for 40 MB, on the import's probe thread. The walks now report how far they read and share a budget of eight times the file's size (at least 1 MiB); real files' candidates fail within a few bytes or are the preview itself. Test: 200,000 fake starts, 0.15 s. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01912WaK6Rmew3wxZuPyX7E8
Merge PR #393
2026-10-08 22:03:26 +00:00 · 2026-10-08 22:00:34 +00:00 · 2026-10-08 22:00:10 +00:00 · 2026-10-09 04:43:24 +07:00 · 2026-10-08 21:26:34 +00:00 · 2026-10-08 21:26:34 +00:00
316 changed files with 62544 additions and 3162 deletions
@@ -27,6 +27,12 @@ jobs:
    timeout-minutes: 300
    steps:
      - uses: actions/checkout@v4
+      # Optional font build input, so the Japanese font tests run (they skip without it).
+      - uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4
+        with:
+          repository: storytold/craft-fonts
+          ref: 8dcdacd5153e64560d109541a47d806f26f048c0
+          path: craft-fonts
      - name: Build and test in a FreeBSD VM
        uses: vmactions/freebsd-vm@c46abacb49f09938ca4e1702d15d836285d694cc # v1
        with:
@@ -44,5 +50,6 @@ jobs:
            # The checkout is synced in under another owner; let tests that call git read it.
            git config --global --add safe.directory "*"
            rustc --version
+            export CRAFT_FONTS_DIR="$PWD/craft-fonts" CRAFT_FONTS_REQUIRED=1
            CARGO_PROFILE_DEV_DEBUG=0 cargo build --workspace --all-targets --locked
            CARGO_PROFILE_DEV_DEBUG=0 cargo test --workspace --locked
@@ -47,7 +47,22 @@ jobs:
      - name: XML, desktop entry, AppStream, Flatpak manifest
        run: |
          xmllint --noout packaging/windows/lightcraft.wxs packaging/macos/*.plist* packaging/linux/*.xml*
+          # Windows Installer needs Icon ids ending in .ico or .exe, or shortcuts show a blank icon.
+          if grep -oE '<Icon Id="[^"]*"' packaging/windows/lightcraft.wxs | grep -vE '\.(ico|exe)"$'; then
+            echo "::error::Icon Id must end in .ico or .exe"; exit 1
+          fi
          desktop-file-validate packaging/linux/ai.storyteller.lightcraft.desktop
          sed -e 's/@VERSION@/0.0.0/' -e 's/@DATE@/2026-01-01/' packaging/linux/ai.storyteller.lightcraft.metainfo.xml.in >"$RUNNER_TEMP/ai.storyteller.lightcraft.metainfo.xml"
          appstreamcli validate --no-net --explain "$RUNNER_TEMP/ai.storyteller.lightcraft.metainfo.xml"
-          python3 -c "import yaml; m = yaml.safe_load(open('packaging/linux/flatpak/ai.storyteller.lightcraft.yml')); assert m['id'] == 'ai.storyteller.lightcraft' and m['command'] == 'lightcraft'"
+          python3 - <<'EOF'
+          import yaml
+          src = yaml.safe_load(open("packaging/linux/flatpak/ai.storyteller.lightcraft.yml"))
+          bundle = yaml.safe_load(open("packaging/linux/flatpak/ai.storyteller.lightcraft.bundle.yml"))
+          for m in (src, bundle):
+              assert m["id"] == "ai.storyteller.lightcraft" and m["command"] == "lightcraft", m["id"]
+          for key in ("runtime", "runtime-version", "sdk", "finish-args"):
+              assert src[key] == bundle[key], f"Flatpak manifests disagree on {key}: {src[key]} vs {bundle[key]}"
+          print("Flatpak manifests ok")
+          EOF
+      - name: FreeBSD tarball layout (stub binaries)
+        run: bash packaging/freebsd/package.sh --dry-run
@@ -1,9 +1,12 @@
-# Release pipeline: every push to `release` builds signed installers for every platform and
-# creates or updates the draft GitHub Release "LightCraft v<version>". See docs/releasing.md.
+# Release pipeline: every push to `release` builds platform artifacts (signed where credentials
+# are configured) and creates or updates the draft GitHub Release "LightCraft v<version>".
+# See docs/releasing.md.
 #
-# All jobs run in the `release` environment (restricted to the `release` branch), which holds
-# the signing secrets. Every secret is optional: missing ones produce unsigned artifacts and a
-# warning, never a failed build.
+# The signing jobs (macOS, Windows) and the draft-release job run in the `release` environment
+# (restricted to the `release` branch), which holds the signing secrets. Every secret is optional:
+# missing ones produce unsigned artifacts and a warning, never a failed build. The jobs that sign
+# nothing (version, Linux, Flatpak, FreeBSD, web) run without it, so a dispatch on any branch is
+# a dry run of them; the release job needs the signed jobs, so a branch run never drafts a release.
 name: Release

 on:
@@ -35,7 +38,7 @@ jobs:
  version:
    name: version
    runs-on: ubuntu-latest
-    environment: release
+    # No `environment: release` here or on the other jobs that sign nothing: no release secrets.
    outputs:
      version: ${{ steps.v.outputs.version }}
      date: ${{ steps.v.outputs.date }}
@@ -63,13 +66,19 @@ jobs:
  macos:
    name: macOS universal
    needs: version
-    runs-on: macos-15
+    runs-on: macos-15-xlarge  # M2 Pro larger runner; use only in release.yml (actions_macos_xl budget caps spend)
    environment: release
    env:
      LIGHTCRAFT_VERSION: ${{ needs.version.outputs.version }}
      LIGHTCRAFT_BUILD_DATE: ${{ needs.version.outputs.date }}
    steps:
      - uses: actions/checkout@v4
+      # Fonts (optional build input; required for releases): see craftrules standards/fonts.md.
+      - uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4
+        with:
+          repository: storytold/craft-fonts
+          ref: 8dcdacd5153e64560d109541a47d806f26f048c0 # bump deliberately
+          path: craft-fonts
      - uses: dtolnay/rust-toolchain@stable
        with:
          targets: aarch64-apple-darwin, x86_64-apple-darwin
@@ -87,6 +96,8 @@ jobs:
        run: packaging/macos/import-cert.sh
      - name: Build, sign, notarize
        env:
+          CRAFT_FONTS_DIR: ${{ github.workspace }}/craft-fonts
+          CRAFT_FONTS_REQUIRED: "1"
          APPLE_ID: ${{ secrets.APPLE_ID }}
          APPLE_PASSWORD: ${{ secrets.APPLE_PASSWORD }}
          APPLE_TEAM_ID: ${{ secrets.APPLE_TEAM_ID }}
@@ -112,11 +123,20 @@ jobs:
        include:
          - { arch: x64, target: x86_64-pc-windows-msvc }
          - { arch: x86, target: i686-pc-windows-msvc }
+          # Windows on ARM: cross-compiled on the x64 runner, so signing and WiX run as above.
+          # .github/workflows/windows-arm64.yml installs and runs it on ARM64 hardware.
+          - { arch: arm64, target: aarch64-pc-windows-msvc }
    env:
      LIGHTCRAFT_VERSION: ${{ needs.version.outputs.version }}
      LIGHTCRAFT_BUILD_DATE: ${{ needs.version.outputs.date }}
    steps:
      - uses: actions/checkout@v4
+      # Fonts (optional build input; required for releases): see craftrules standards/fonts.md.
+      - uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4
+        with:
+          repository: storytold/craft-fonts
+          ref: 8dcdacd5153e64560d109541a47d806f26f048c0 # bump deliberately
+          path: craft-fonts
      - uses: dtolnay/rust-toolchain@stable
        with:
          targets: ${{ matrix.target }}
@@ -133,6 +153,8 @@ jobs:
      - name: Build, sign, package
        shell: pwsh
        env:
+          CRAFT_FONTS_DIR: ${{ github.workspace }}/craft-fonts
+          CRAFT_FONTS_REQUIRED: "1"
          WINDOWS_CERTIFICATE: ${{ secrets.WINDOWS_CERTIFICATE }}
          WINDOWS_CERTIFICATE_PASSWORD: ${{ secrets.WINDOWS_CERTIFICATE_PASSWORD }}
          AZURE_TENANT_ID: ${{ secrets.AZURE_TENANT_ID }}
@@ -154,7 +176,6 @@ jobs:
    # The oldest GitHub-hosted image, so the binaries only need glibc >= 2.35 (Ubuntu 22.04+,
    # Debian 12+, Fedora 36+, RHEL 10). See docs/releasing.md.
    runs-on: ${{ matrix.runner }}
-    environment: release
    strategy:
      fail-fast: false
      matrix:
@@ -167,12 +188,18 @@ jobs:
      NFPM_VERSION: 2.47.0
    steps:
      - uses: actions/checkout@v4
+      # Fonts (optional build input; required for releases): see craftrules standards/fonts.md.
+      - uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4
+        with:
+          repository: storytold/craft-fonts
+          ref: 8dcdacd5153e64560d109541a47d806f26f048c0 # bump deliberately
+          path: craft-fonts
      - name: Install build and packaging tools
        run: |
          sudo apt-get update
          sudo apt-get install -y --no-install-recommends \
            libxkbcommon-dev libwayland-dev libx11-dev libxrandr-dev libxi-dev libgl1-mesa-dev \
-            desktop-file-utils appstream python3-yaml
+            desktop-file-utils appstream python3-yaml zsync
          curl -fsSL -o "$RUNNER_TEMP/nfpm.deb" \
            "https://github.com/goreleaser/nfpm/releases/download/v${NFPM_VERSION}/nfpm_${NFPM_VERSION}_${{ matrix.deb }}.deb"
          sudo dpkg -i "$RUNNER_TEMP/nfpm.deb"
@@ -184,6 +211,9 @@ jobs:
        if: inputs.version != ''
        run: cargo xtask version set "$LIGHTCRAFT_VERSION"
      - name: Build and package (AppImage, deb, rpm, tar.gz)
+        env:
+          CRAFT_FONTS_DIR: ${{ github.workspace }}/craft-fonts
+          CRAFT_FONTS_REQUIRED: "1"
        run: packaging/linux/package.sh
      - name: Check the packages
        run: |
@@ -194,6 +224,9 @@ jobs:
          for appimage in dist/release/*.AppImage; do
            chmod +x "$appimage"
            APPIMAGE_EXTRACT_AND_RUN=1 "$appimage" --version
+            # Update information is embedded, and the .zsync for delta updates sits beside it.
+            "$appimage" --appimage-updateinformation | grep -F 'gh-releases-zsync|'
+            test -s "$appimage.zsync"
          done
      - uses: actions/upload-artifact@v4
        with:
@@ -201,17 +234,110 @@ jobs:
          path: dist/release/*
          if-no-files-found: error

+  flatpak:
+    name: Flatpak ${{ matrix.arch }}
+    needs: [version, linux]
+    # Repackages the Linux job's tarball (the same binaries as the AppImage/deb/rpm); no Rust
+    # build here. 24.04 for a newer flatpak-builder (1.4) than 22.04 ships.
+    runs-on: ${{ matrix.runner }}
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - { arch: x86_64, runner: ubuntu-24.04 }
+          - { arch: aarch64, runner: ubuntu-24.04-arm }
+    env:
+      LIGHTCRAFT_VERSION: ${{ needs.version.outputs.version }}
+      LIGHTCRAFT_BUILD_DATE: ${{ needs.version.outputs.date }}
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/download-artifact@v4
+        with:
+          name: release-linux-${{ matrix.arch }}
+          path: dist/linux
+      - name: Install flatpak-builder
+        run: |
+          sudo apt-get update
+          # librsvg2-common: the SVG pixbuf loader. flatpak-builder runs the host's
+          # `appstreamcli compose`, which renders the scalable icon and fails without it.
+          sudo apt-get install -y --no-install-recommends flatpak flatpak-builder librsvg2-common
+          # Ubuntu 24.04's AppArmor blocks the unprivileged user namespaces bubblewrap needs.
+          sudo sysctl -w kernel.apparmor_restrict_unprivileged_userns=0
+      - name: Build the Flatpak bundle
+        run: packaging/linux/flatpak-bundle.sh "dist/linux/lightcraft-$LIGHTCRAFT_VERSION-linux-${{ matrix.arch }}.tar.gz"
+      - uses: actions/upload-artifact@v4
+        with:
+          name: release-flatpak-${{ matrix.arch }}
+          path: dist/release/*.flatpak
+          if-no-files-found: error
+
+  freebsd:
+    name: FreeBSD x86_64
+    needs: version
+    # GitHub has no FreeBSD runners: build in a FreeBSD 14.3 VM, the same image and packages as
+    # .github/workflows/freebsd.yml.
+    runs-on: ubuntu-latest
+    timeout-minutes: 180
+    env:
+      LIGHTCRAFT_VERSION: ${{ needs.version.outputs.version }}
+      LIGHTCRAFT_BUILD_DATE: ${{ needs.version.outputs.date }}
+    steps:
+      - uses: actions/checkout@v4
+      # Fonts (optional build input; required for releases): see craftrules standards/fonts.md.
+      - uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4
+        with:
+          repository: storytold/craft-fonts
+          ref: 8dcdacd5153e64560d109541a47d806f26f048c0 # bump deliberately
+          path: craft-fonts
+      - name: Build and package in a FreeBSD VM (tar.gz)
+        # vmactions/freebsd-vm v1.5.9, pinned by commit (it runs our build).
+        uses: vmactions/freebsd-vm@c46abacb49f09938ca4e1702d15d836285d694cc
+        with:
+          release: "14.3"
+          usesh: true
+          cpu: 4
+          mem: 12288
+          # Passed into the VM by name; never templated into the script below.
+          envs: "LIGHTCRAFT_VERSION LIGHTCRAFT_BUILD_DATE LIGHTCRAFT_BUILD_SHA INPUT_VERSION"
+          # The FreeBSD CI packages, plus bash for the packaging script.
+          prepare: |
+            pkg install -y bash git curl pkgconf cmake python3 libxkbcommon wayland libX11 libXcursor libXrandr libXi libxcb mesa-libs vulkan-loader gtk3 fontconfig freetype2 alsa-lib
+            curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --profile minimal --default-toolchain stable
+          run: |
+            set -e
+            . "$HOME/.cargo/env"
+            git config --global --add safe.directory "$PWD"
+            # Build outside the checkout so only dist/ is copied back out of the VM (copying the
+            # target dir back fails on large builds). 4 jobs: more runs the VM out of memory.
+            export CARGO_TARGET_DIR=/var/tmp/lightcraft-target CARGO_BUILD_JOBS=4
+            if [ -n "$INPUT_VERSION" ]; then cargo xtask version set "$LIGHTCRAFT_VERSION"; fi
+            # craft-fonts was checked out next to the sources and synced into the VM with them.
+            export CRAFT_FONTS_DIR="$PWD/craft-fonts" CRAFT_FONTS_REQUIRED=1
+            bash packaging/freebsd/package.sh
+            tar -tzf dist/release/lightcraft-*-freebsd-x86_64.tar.gz \
+              | grep -E '/bin/lightcraft$|/bin/lightcraft-cli$|/share/applications/ai\.storyteller\.lightcraft\.desktop$|/share/doc/lightcraft/LICENSE-MIT$'
+      - uses: actions/upload-artifact@v4
+        with:
+          name: release-freebsd-x86_64
+          path: dist/release/*
+          if-no-files-found: error
+
  web:
    name: Web (wasm)
    needs: version
    runs-on: ubuntu-latest
-    environment: release
    env:
      LIGHTCRAFT_VERSION: ${{ needs.version.outputs.version }}
      LIGHTCRAFT_BUILD_DATE: ${{ needs.version.outputs.date }}
      WASM_BINDGEN_VERSION: 0.2.129
    steps:
      - uses: actions/checkout@v4
+      # Fonts (optional build input; required for releases): see craftrules standards/fonts.md.
+      - uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4
+        with:
+          repository: storytold/craft-fonts
+          ref: 8dcdacd5153e64560d109541a47d806f26f048c0 # bump deliberately
+          path: craft-fonts
      - uses: dtolnay/rust-toolchain@stable
        with:
          targets: wasm32-unknown-unknown
@@ -221,13 +347,17 @@ jobs:
      - name: Install wasm-bindgen CLI
        run: |
          # Must match the wasm-bindgen version in Cargo.lock exactly (cargo xtask web checks it).
-          command -v wasm-bindgen >/dev/null && wasm-bindgen --version | grep -q "$WASM_BINDGEN_VERSION" \
-            || cargo install wasm-bindgen-cli --version "$WASM_BINDGEN_VERSION" --locked
+          if ! { command -v wasm-bindgen >/dev/null && wasm-bindgen --version | grep -q "$WASM_BINDGEN_VERSION"; }; then
+            cargo install wasm-bindgen-cli --version "$WASM_BINDGEN_VERSION" --locked
+          fi
          wasm-bindgen --version
      - name: Apply version override
        if: inputs.version != ''
        run: cargo xtask version set "$LIGHTCRAFT_VERSION"
      - name: Build and zip
+        env:
+          CRAFT_FONTS_DIR: ${{ github.workspace }}/craft-fonts
+          CRAFT_FONTS_REQUIRED: "1"
        run: packaging/web/package.sh
      - uses: actions/upload-artifact@v4
        with:
@@ -237,7 +367,7 @@ jobs:

  release:
    name: Draft GitHub Release
-    needs: [version, macos, windows, linux, web]
+    needs: [version, macos, windows, linux, flatpak, freebsd, web]
    runs-on: ubuntu-latest
    environment: release
    permissions:
@@ -0,0 +1,95 @@
+# Windows on ARM: package the ARM64 release the way release.yml does (cross-compiled on an x64
+# runner, unsigned here), then install that MSI on a Windows 11 ARM64 runner, check the installed
+# binaries are ARM64, run the CLI natively, and uninstall. (A native ARM64 `cargo test` job is left
+# out for now: PdfCraft saw an intermittent access violation in egui UI tests there.)
+name: Windows ARM64
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    paths:
+      - Cargo.toml
+      - Cargo.lock
+      - "**/Cargo.toml"
+      - "**/build.rs"
+      - .github/workflows/windows-arm64.yml
+      - packaging/windows/**
+  schedule:
+    - cron: "41 4 * * 1" # weekly, so drift in the runner images shows up
+  workflow_dispatch:
+
+concurrency:
+  group: windows-arm64-${{ github.ref }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read
+
+env:
+  CARGO_TERM_COLOR: always
+  CARGO_INCREMENTAL: 0
+
+jobs:
+  package:
+    name: package (cross-compiled on x64)
+    runs-on: windows-latest
+    timeout-minutes: 90
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@89b12181fb390509a0842a86cc55eeb8eb928c1d # stable
+        with:
+          targets: aarch64-pc-windows-msvc
+      - uses: Swatinem/rust-cache@6323deb102c322ba6fcbdcafc7e3dddab59af2b6 # v2
+        with:
+          key: windows-arm64-package
+      - name: Install WiX
+        shell: pwsh
+        run: dotnet tool install --global wix --version 5.0.2
+      - name: Build and package (unsigned)
+        shell: pwsh
+        env:
+          DIST: ${{ github.workspace }}\dist\arm64
+        run: ./packaging/windows/package.ps1 -Arch arm64
+      - uses: actions/upload-artifact@v4
+        with:
+          name: lightcraft-windows-arm64
+          path: dist/arm64/*
+          if-no-files-found: error
+          retention-days: 7
+
+  install:
+    name: install and run on ARM64
+    needs: package
+    runs-on: windows-11-arm
+    timeout-minutes: 30
+    steps:
+      - uses: actions/download-artifact@v4
+        with:
+          name: lightcraft-windows-arm64
+          path: dist
+      - name: Install the MSI, check it, run it, uninstall it
+        shell: pwsh
+        run: |
+          $ErrorActionPreference = 'Stop'
+          $msi = (Get-ChildItem dist/*.msi | Select-Object -First 1).FullName
+          $p = Start-Process msiexec.exe -ArgumentList '/i', "`"$msi`"", '/qn', '/l*v', 'install.log' -Wait -PassThru
+          if ($p.ExitCode -ne 0) { Get-Content install.log -Tail 60; throw "msiexec /i exited $($p.ExitCode)" }
+          $dir = Join-Path $env:ProgramFiles 'LightCraft'
+          foreach ($exe in 'lightcraft.exe', 'lightcraft-cli.exe') {
+            $path = Join-Path $dir $exe
+            if (-not (Test-Path $path)) { throw "$exe not installed in $dir" }
+            $bytes = [System.IO.File]::ReadAllBytes($path)
+            $machine = [BitConverter]::ToUInt16($bytes, [BitConverter]::ToInt32($bytes, 0x3C) + 4)
+            if ($machine -ne 0xAA64) { throw "$exe is for machine 0x$('{0:X}' -f $machine), not ARM64" }
+            Write-Output "ok $path (ARM64)"
+          }
+          # The installed CLI runs natively on ARM64.
+          $cli = Join-Path $dir 'lightcraft-cli.exe'
+          $out = & $cli --version 2>&1 | Out-String
+          if ($LASTEXITCODE -ne 0) { Write-Output $out; throw "lightcraft-cli --version exited $LASTEXITCODE" }
+          Write-Output "ok lightcraft-cli --version: $($out.Trim())"
+          $p = Start-Process msiexec.exe -ArgumentList '/x', "`"$msi`"", '/qn' -Wait -PassThru
+          if ($p.ExitCode -ne 0) { throw "msiexec /x exited $($p.ExitCode)" }
+          if (Test-Path (Join-Path $dir 'lightcraft.exe')) { throw 'uninstall left lightcraft.exe behind' }
+          Write-Output 'ok uninstalled'
@@ -7,3 +7,10 @@ plan/
 /log
 .DS_Store
 .claude/
+/craft-fonts
+# nix build / nix develop
+/result
+/result-*
+# model weights are never committed (SAM 3: docs/ai-masks.md)
+*.safetensors
+*.safetensors.part
@@ -1,6 +1,6 @@
 # LightCraft — instructions for agents

-LightCraft is a clean-room, open-source, pure-Rust photo library + non-destructive raw developer targeting Adobe Lightroom parity (and beyond). Native on macOS, Windows, Linux; web via WASM. Sibling of `../printcraft` (Acrobat), `../photocraft` (Photoshop), `../drawcraft` (Illustrator) and `../filmcraft` (Premiere), with the same conventions.
+LightCraft is a clean-room, open-source, pure-Rust photo library + non-destructive raw developer targeting Adobe Lightroom parity (and beyond). Native on macOS, Windows, Linux; web via WASM. Sibling of `../pdfcraft` (Acrobat), `../photocraft` (Photoshop), `../vectorcraft` (Illustrator) and `../filmcraft` (Premiere), with the same conventions.

 ## Start every session here
 1. Read `plan/STATUS.md` (current milestone, next unchecked task, blockers).
@@ -62,10 +62,24 @@ of it. Full standard: `../craftrules/standards/never-crash.md`
 ## Assets: icons, images, fonts (ABSOLUTE RULE — never violate)
 - **Never use any iconography, image, artwork, font, sound or other asset from Adobe products** (no Lightroom/Creative Cloud icons, no screenshots, no presets/profiles/LUTs, no UI bitmaps — not even as a temporary placeholder or "reference copy"). Observing Adobe's UI to imitate *layout and behaviour* is allowed; copying or tracing its assets is not.
 - **This includes Adobe's open-licensed assets**: no Source Sans/Serif/Code or Source Han fonts, no Adobe Fonts, no
-  Adobe-published icon sets, sample photos, colour profiles or LUTs — even when OFL/MIT. The UI font is Inter (OFL).
+  Adobe-published icon sets, sample photos, colour profiles or LUTs — even when OFL/MIT. The UI font is Inter (OFL);
+  Japanese and Chinese fonts come from craft-fonts (below). **One exception (maintainer decision, 2026-10-07): Noto
+  Sans/Serif CJK** (Google-branded, OFL, co-developed with Adobe as Source Han) is allowed via craft-fonts for Chinese
+  text, because nearly every OFL Chinese face derives from it. Use it unmodified under its OFL; this does not open the
+  door to Source Han under Adobe's name or to any other Adobe asset.
 - Every asset in the repository must be one of: **our own original work** (e.g. icons drawn in code as vectors, procedurally generated demo photos), **public domain / CC0**, **Creative Commons** (CC-BY / CC-BY-SA with attribution honoured), **OFL** (fonts), or **permissive open-source** (MIT/Apache-2.0/BSD/ISC) — or contributed by a person who created the asset and licenses it openly.
 - **Exception: `docs/brand/`.** The ArtCraft name, wordmark and logos there are ArtCraft Team trademarks, not open source and not covered by LightCraft's MIT OR Apache-2.0 licence (`LICENSE-MIT`, `LICENSE-APACHE`, `NOTICE`); their terms are in `docs/brand/LICENSE-brand.txt`. Use them only unmodified and never redraw, recolour or derive from them.
 - **Every asset must have an entry in `assets/ATTRIBUTION.md`** (path, title, author/creator, source URL or "original work", licence, date added, modifications) and its licence text when required (e.g. `assets/fonts/OFL-*.txt`). Add the entry in the same commit as the asset. Assets without an attribution entry must not be committed.
+- **Fonts live in [storytold/craft-fonts](https://github.com/storytold/craft-fonts), never in this repo.** Don't commit
+  font files here (Inter, already in `assets/fonts/`, is the one exception); add new fonts to craft-fonts. LightCraft
+  uses it as the optional build input `CRAFT_FONTS_DIR`: `git clone https://github.com/storytold/craft-fonts ../craft-fonts`
+  then `CRAFT_FONTS_DIR=../craft-fonts cargo run -p lightcraft` (or any cargo/xtask command). `crates/engine/build.rs`
+  embeds the manifest's fonts as `lightcraft_engine::CRAFT_FONTS` (wasm32: BIZ UDPGothic Regular only); the UI
+  (`theme::font_definitions`) and the export watermark renderer use its CJK faces (picked by script) as fallbacks after Inter. Unset,
+  `CRAFT_FONTS` is empty: everything builds, tests and runs, but Japanese text has no glyphs. Releases always build
+  with it (`release.yml`, `CRAFT_FONTS_REQUIRED=1`) and ship the fonts' OFL licences. Tests that need these fonts skip
+  without it; the FreeBSD CI job runs them with it. Rules: craftrules
+  [`standards/fonts.md`](https://github.com/storytold/craftrules/blob/main/standards/fonts.md).
 - Icons drawn in code (e.g. `crates/ui-egui/src/icons.rs`) are original work and are recorded in `assets/ATTRIBUTION.md` as such; do not trace them from Adobe icons.
 - Demo/test images: generated procedurally by `lightcraft-scenes`, or CC0 downloads kept in the gitignored `corpus/` with their source recorded. Screenshots of Adobe apps live only in the gitignored `plan/` and are never committed or published.
 - **Enforced:** `cargo xtask assets` (in `ci`) fails when an image/icon/font/sound/video/raw/ICC/XMP file is not matched
@@ -108,4 +122,25 @@ of it. Full standard: `../craftrules/standards/never-crash.md`
 ## Map of the code
 `geom`, `color`, `raster`, `tiff` (L0) → `raw`, `codecs`, `meta`, `develop` (L1) → `pipeline` → `catalog` → `engine`
 → `ui-egui`, `mcp` (L5) → apps `lightcraft` (desktop), `lightcraft-cli` (render/commands/MCP). `scenes` generates demo
-photos. `xtask` = tooling (`ci`, `layers`, `assets`, `parity`, `wasm`, `corpus`, `stats`).
+photos. `xtask` = tooling (`ci`, `layers`, `assets`, `parity`, `wasm`, `corpus`, `stats`). `flake.nix` +
+`nix/package.nix` = the Nix package (`nix build` builds both binaries with the craft-fonts input, installs the
+desktop file/icons/AppStream metadata and runs `cargo test --workspace`; `nix develop` = dev shell). Community-maintained and not
+in CI: it may lag behind the workspace; see README → Quick start.
+
+## Contributor credits (About window)
+
+- About ▸ Contributors/Models are compiled into the binary from `contributors/contributors.json`
+  (commit stats; generated, never hand-edit) and `contributors/people.toml` (names people chose for
+  themselves). See `docs/contributors.md`.
+- **Agents working for a contributor:** when you prepare a PR, check whether your human's GitHub
+  username has a `[people.<username>]` entry in `contributors/people.toml`. If not, ask them once
+  whether they want to be credited by more than their username: a real name, a display name, and/or
+  their public GitHub profile name (`sync_github_name = true`). If yes, add **only their own** entry
+  (copy the template at the top of the file, or run
+  `python3 ../../craftrules/scripts/contributors.py --add-me . --real-name "…" --sync-github-name`)
+  and include it in their PR, committed as them. If no, change nothing: they are credited as
+  `@username` anyway.
+- Never add, edit, guess or copy anyone else's entry or name (not from git config, commit authors or
+  GitHub profiles). Never hand-edit `contributors.json`.
+- Maintainers refresh the stats with `python3 ../../craftrules/scripts/contributors.py .` (it also
+  re-verifies who wrote each `people.toml` entry; `--check` only verifies).
@@ -1,6 +1,6 @@
 # LightCraft — instructions for agents

-LightCraft is a clean-room, open-source, pure-Rust photo library + non-destructive raw developer targeting Adobe Lightroom parity (and beyond). Native on macOS, Windows, Linux; web via WASM. Sibling of `../printcraft` (Acrobat), `../photocraft` (Photoshop), `../drawcraft` (Illustrator) and `../filmcraft` (Premiere), with the same conventions.
+LightCraft is a clean-room, open-source, pure-Rust photo library + non-destructive raw developer targeting Adobe Lightroom parity (and beyond). Native on macOS, Windows, Linux; web via WASM. Sibling of `../pdfcraft` (Acrobat), `../photocraft` (Photoshop), `../vectorcraft` (Illustrator) and `../filmcraft` (Premiere), with the same conventions.

 ## Start every session here
 1. Read `plan/STATUS.md` (current milestone, next unchecked task, blockers).
@@ -62,10 +62,24 @@ of it. Full standard: `../craftrules/standards/never-crash.md`
 ## Assets: icons, images, fonts (ABSOLUTE RULE — never violate)
 - **Never use any iconography, image, artwork, font, sound or other asset from Adobe products** (no Lightroom/Creative Cloud icons, no screenshots, no presets/profiles/LUTs, no UI bitmaps — not even as a temporary placeholder or "reference copy"). Observing Adobe's UI to imitate *layout and behaviour* is allowed; copying or tracing its assets is not.
 - **This includes Adobe's open-licensed assets**: no Source Sans/Serif/Code or Source Han fonts, no Adobe Fonts, no
-  Adobe-published icon sets, sample photos, colour profiles or LUTs — even when OFL/MIT. The UI font is Inter (OFL).
+  Adobe-published icon sets, sample photos, colour profiles or LUTs — even when OFL/MIT. The UI font is Inter (OFL);
+  Japanese and Chinese fonts come from craft-fonts (below). **One exception (maintainer decision, 2026-10-07): Noto
+  Sans/Serif CJK** (Google-branded, OFL, co-developed with Adobe as Source Han) is allowed via craft-fonts for Chinese
+  text, because nearly every OFL Chinese face derives from it. Use it unmodified under its OFL; this does not open the
+  door to Source Han under Adobe's name or to any other Adobe asset.
 - Every asset in the repository must be one of: **our own original work** (e.g. icons drawn in code as vectors, procedurally generated demo photos), **public domain / CC0**, **Creative Commons** (CC-BY / CC-BY-SA with attribution honoured), **OFL** (fonts), or **permissive open-source** (MIT/Apache-2.0/BSD/ISC) — or contributed by a person who created the asset and licenses it openly.
 - **Exception: `docs/brand/`.** The ArtCraft name, wordmark and logos there are ArtCraft Team trademarks, not open source and not covered by LightCraft's MIT OR Apache-2.0 licence (`LICENSE-MIT`, `LICENSE-APACHE`, `NOTICE`); their terms are in `docs/brand/LICENSE-brand.txt`. Use them only unmodified and never redraw, recolour or derive from them.
 - **Every asset must have an entry in `assets/ATTRIBUTION.md`** (path, title, author/creator, source URL or "original work", licence, date added, modifications) and its licence text when required (e.g. `assets/fonts/OFL-*.txt`). Add the entry in the same commit as the asset. Assets without an attribution entry must not be committed.
+- **Fonts live in [storytold/craft-fonts](https://github.com/storytold/craft-fonts), never in this repo.** Don't commit
+  font files here (Inter, already in `assets/fonts/`, is the one exception); add new fonts to craft-fonts. LightCraft
+  uses it as the optional build input `CRAFT_FONTS_DIR`: `git clone https://github.com/storytold/craft-fonts ../craft-fonts`
+  then `CRAFT_FONTS_DIR=../craft-fonts cargo run -p lightcraft` (or any cargo/xtask command). `crates/engine/build.rs`
+  embeds the manifest's fonts as `lightcraft_engine::CRAFT_FONTS` (wasm32: BIZ UDPGothic Regular only); the UI
+  (`theme::font_definitions`) and the export watermark renderer use its CJK faces (picked by script) as fallbacks after Inter. Unset,
+  `CRAFT_FONTS` is empty: everything builds, tests and runs, but Japanese text has no glyphs. Releases always build
+  with it (`release.yml`, `CRAFT_FONTS_REQUIRED=1`) and ship the fonts' OFL licences. Tests that need these fonts skip
+  without it; the FreeBSD CI job runs them with it. Rules: craftrules
+  [`standards/fonts.md`](https://github.com/storytold/craftrules/blob/main/standards/fonts.md).
 - Icons drawn in code (e.g. `crates/ui-egui/src/icons.rs`) are original work and are recorded in `assets/ATTRIBUTION.md` as such; do not trace them from Adobe icons.
 - Demo/test images: generated procedurally by `lightcraft-scenes`, or CC0 downloads kept in the gitignored `corpus/` with their source recorded. Screenshots of Adobe apps live only in the gitignored `plan/` and are never committed or published.
 - **Enforced:** `cargo xtask assets` (in `ci`) fails when an image/icon/font/sound/video/raw/ICC/XMP file is not matched
@@ -108,4 +122,7 @@ of it. Full standard: `../craftrules/standards/never-crash.md`
 ## Map of the code
 `geom`, `color`, `raster`, `tiff` (L0) → `raw`, `codecs`, `meta`, `develop` (L1) → `pipeline` → `catalog` → `engine`
 → `ui-egui`, `mcp` (L5) → apps `lightcraft` (desktop), `lightcraft-cli` (render/commands/MCP). `scenes` generates demo
-photos. `xtask` = tooling (`ci`, `layers`, `assets`, `parity`, `wasm`, `corpus`, `stats`).
+photos. `xtask` = tooling (`ci`, `layers`, `assets`, `parity`, `wasm`, `corpus`, `stats`). `flake.nix` +
+`nix/package.nix` = the Nix package (`nix build` builds both binaries with the craft-fonts input, installs the
+desktop file/icons/AppStream metadata and runs `cargo test --workspace`; `nix develop` = dev shell). Community-maintained and not
+in CI: it may lag behind the workspace; see README → Quick start.
@@ -3,7 +3,7 @@ resolver = "3"
 members = ["crates/*", "apps/*", "xtask"]

 [workspace.package]
-version = "0.2.0"
+version = "0.4.0"
 edition = "2024"
 license = "MIT OR Apache-2.0"
 rust-version = "1.90"
@@ -29,6 +29,8 @@ lightcraft-merge = { path = "crates/merge" }
 lightcraft-engine = { path = "crates/engine" }
 lightcraft-ui-egui = { path = "crates/ui-egui" }
 lightcraft-mcp = { path = "crates/mcp" }
+lightcraft-fetch = { path = "crates/fetch" }
+lightcraft-segment = { path = "crates/segment" }

 # foundation
 thiserror = "2"
@@ -62,6 +64,10 @@ jxl-oxide = { version = "0.12", default-features = false }
 ravif = { version = "0.13", default-features = false, features = ["threading"] } # no "asm": it needs nasm (non-Rust)

 # gpu (crates/gpu; native backends only, no GL: everything stays pure Rust)
+# SAM 3 inference (lightcraft-segment). 0.9.2: later releases pull `tokenizers` with the
+# Oniguruma C library into candle-core, and the product is pure Rust.
+candle-core = { version = "=0.9.2", default-features = false }
+candle-nn = { version = "=0.9.2", default-features = false }
 wgpu = { version = "30", default-features = false, features = ["std", "parking_lot", "metal", "vulkan", "dx12", "wgsl"] }
 pollster = "1"

@@ -15,6 +15,20 @@ list (author, source, license) is in assets/ATTRIBUTION.md.
 Inter (assets/fonts/Inter-*.ttf) — SIL Open Font License 1.1. See assets/fonts/OFL-Inter.txt.
 Showcase photographs by Ansel Adams, Dorothea Lange and NASA (docs/images/) — public domain. See assets/ATTRIBUTION.md.

-BIZ UDMincho: Copyright 2022 The BIZ UDMincho Project Authors
-(https://github.com/googlefonts/morisawa-biz-ud-mincho). SIL Open Font License 1.1;
-see assets/fonts/OFL-BIZUDMincho.txt.
+crates/segment (lightcraft-segment) ports the SAM 3 model code of Hugging Face Transformers
+(https://github.com/huggingface/transformers, src/transformers/models/sam3 and sam3_tracker),
+Copyright The HuggingFace Team and Meta Platforms, Inc., licensed under the Apache License 2.0.
+The port was modified by the LightCraft contributors (2026): translated from Python/PyTorch to
+Rust on candle and restructured; each ported file says so. Because of this, crates/segment is
+licensed under the Apache License 2.0 only (LICENSE-APACHE), not under the MIT option.
+
+The SAM 3 weights are not part of LightCraft and are never distributed with it. A user downloads
+the facebook/sam3 checkpoint only when they choose to (in the app, or by hand), under Meta's SAM
+License (https://github.com/facebookresearch/sam3/blob/main/LICENSE), a separate, non-OSI
+licence. See docs/ai-masks.md.
+
+Builds made with craft-fonts (the optional CRAFT_FONTS_DIR build input; all official releases)
+also embed the fonts listed in https://github.com/storytold/craft-fonts/blob/main/ATTRIBUTION.md
+(the Japanese fonts BIZ UDPGothic, BIZ UDMincho and Shippori Mincho; the web build embeds only BIZ
+UDPGothic Regular), under the SIL Open Font License 1.1. Release packages include each font's
+licence as OFL-<family>.txt.
@@ -59,6 +59,7 @@
  <a href="#feature-status">Status</a> ·
  <a href="#quick-start">Quick start</a> ·
  <a href="ROADMAP.md">Roadmap</a> ·
+  <a href="#downloads">Downloads</a> ·
  <a href="#the-crafting-apps">Crafting Apps</a>
 </p>

@@ -200,7 +201,7 @@ A library that stays out of your way: **All Photos**, **Recently Added**, **Pick
 **Folders**, and **Recently Deleted**. Rate with <kbd>0</kbd>–<kbd>5</kbd>, flag with <kbd>P</kbd> / <kbd>X</kbd> /
 <kbd>U</kbd>, colour-label with <kbd>6</kbd>–<kbd>9</kbd>. Search understands fields:
 `rating:>3 flag:pick iso:>800 camera:x2 date:2026-04 keyword:mountains`. Every view sorts by capture date,
-import date, edit date, name, rating or size. The justified **Photo Grid** and **Square Grid** views are virtualized,
+import date, edit date, name, rating, size or at random (a stable shuffle; View → Sort → Reshuffle for a new one). The justified **Photo Grid** and **Square Grid** views are virtualized,
 so they stay smooth whether you have forty photos or forty thousand.

 <table>
@@ -233,11 +234,11 @@ lightcraft --control 7980 ~/Pictures/trip
 {"method": "ui.screenshot",    "params": {"path": "after.png"}}
 ```

- **91 engine commands** and **48 UI commands.** List them all with `engine.commands`; read every slider's range,
-  default and current value with `develop.controls`.
- **MCP server.** `lightcraft-cli mcp` gives Claude (or any MCP client) ~100 tools: import, query, develop, mask,
-  render (returned as an image), export. It runs headless, or attached to the running app with screenshots, clicks
-  and gestures. See [docs/mcp.md](docs/mcp.md).
+- **Command registry.** `engine.commands` lists the available commands; `develop.controls` lists every slider's
+  range, default and current value.
+- **MCP server.** `lightcraft-cli mcp` exposes the command registry to Claude (or any MCP client), alongside
+  helpers for import, query, develop, mask, render (returned as an image) and export. It runs headless, or attached
+  to the running app with screenshots, clicks and gestures. See [docs/mcp.md](docs/mcp.md).

  ```sh
  cargo build --release -p lightcraft-cli
@@ -257,9 +258,9 @@ lightcraft --control 7980 ~/Pictures/trip

 ## Fast, native, private

- **Pure Rust, no C.** Our own RAW decoders (DNG, Canon CR2, Sony ARW, Nikon NEF, Fujifilm RAF incl. X-Trans,
-  Panasonic RW2, Pentax PEF, Olympus ORF), our own colour science, our own pipeline. JPEG, PNG, TIFF, WebP, PSD
-  composites and JPEG XL open today.
+- **Pure Rust, no C.** Our own RAW decoders (DNG, Canon CR2/CR3, Sony ARW, Nikon NEF, Fujifilm RAF incl. X-Trans,
+  Panasonic RW2 / Leica RWL, Pentax PEF, Olympus ORF), our own colour science, our own pipeline. JPEG, PNG, TIFF, WebP,
+  PSD composites and JPEG XL open today.
 - **Scene-referred & wide-gamut.** Linear Rec.2020 float internally, Bradford-adapted white balance, gamut mapping
  instead of clipping, a filmic shoulder for raw and pixel-exact pass-through for JPEGs you haven't touched.
 - **Resolution-independent edits.** Radii and brush sizes are relative to the image, so a 400 px preview, your
@@ -287,8 +288,8 @@ LightCraft is young and moving fast. **Where we honestly stand** (details in the
 - **As a day-to-day Lightroom replacement we're nearer 60–70%.** It's great for JPEG/DNG and most Nikon / Sony /
  older-Canon raws on one machine.
 - **The biggest gaps:**
-  - **camera colour calibration:** raws other than DNG develop with a neutral colour matrix today, so colour is muted;
-  - **CR3 and compressed Fujifilm / Olympus raws:** these open as embedded previews only;
+  - **camera colour calibration:** Sony, Nikon, Panasonic, Fujifilm and Canon CR3 raws have guarded estimates from their camera JPEGs, with built-in ILCE-7M4, X-H2S and X-T4 profiles; measured calibration is missing, and other raws or rejected fits retain a neutral matrix;
+  - **compressed Olympus raws and unsupported CR3 variants:** these use embedded JPEG previews when present. Fujifilm lossless/lossy compressed RAF now decodes sensor data; [verification and existing-library reload instructions](docs/raf-compression.md);
  - **AI masks and denoise:** subject and sky selection are classical heuristics;
  - **HDR, video and the Classic Print / Book / Map modules.**
 - **What's next:** see [where we're going](ROADMAP.md#where-were-going).
@@ -301,9 +302,9 @@ LightCraft is young and moving fast. **Where we honestly stand** (details in the
 | Masking: brush, linear, radial, luminance/colour range, add/subtract/intersect | ✅ (AI subject/sky use classical heuristics for now) |
 | Crop, straighten tool + auto straighten, flip, rotate, aspect ratios, overlays | ✅ |
 | Profiles (Color, Neutral, Vivid, Landscape, Portrait, Monochrome: our own looks), presets, versions, history, copy/paste/sync settings | ✅ |
-| Camera colour: DNG files use their own matrices | ✅ · our own calibration for other raws ⬜ (top priority; neutral fallback today) |
+| Camera colour: DNG files use their own matrices | ✅ DNG · 🟡 own Sony/Fujifilm profiles; measured calibration database missing |
 | Native macOS menu bar (generated from the command registry), control channel + every widget addressable, headless UI snapshots | ✅ |
-| RAW: DNG, CR2, ARW, NEF (uncompressed + lossless/lossy compressed), Fujifilm RAF (uncompressed, Bayer + X-Trans), Panasonic RW2, Pentax PEF, Olympus ORF (uncompressed); embedded previews for every format incl. CR3 | ✅ · CR3, compressed RAF/ORF decode ⬜ |
+| RAW: DNG, CR2, CR3 (lossless CRX Bayer and version 0x100/0x200 C-RAW), ARW, NEF (uncompressed + lossless/lossy compressed), Fujifilm RAF (uncompressed + lossless/lossy compressed, Bayer + X-Trans), Panasonic RW2 / Leica RWL / Panasonic RAW (every raw format, DMC-LX1 to DC-S1RM2), Pentax PEF, Olympus ORF (uncompressed); embedded previews for every format incl. CR3 | 🟡 · CR3, compressed ORF decode ⬜ |
 | Detail: sharpening, luminance + colour noise reduction | ✅ · AI Denoise, Super Resolution ⬜ |
 | Remove / Heal / Clone spots (auto source), Visualize Spots, Red Eye and Pet Eye (auto pupil detection, catchlight) | ✅ · content-aware fill, spot pin editing 🚧 |
 | Export: JPEG / PNG / TIFF / WebP / AVIF / DNG / original, sizing, file-size limit, output sharpening, naming templates, batch, metadata policy, text or image watermark | ✅ · HDR export ⬜ |
@@ -311,7 +312,7 @@ LightCraft is young and moving fast. **Where we honestly stand** (details in the
 | Import: Add in place / Copy / Move, rename and folder templates, devices, duplicate detection, watched folders; Local folder browsing | ✅ |
 | MCP server (headless or live app, persistent libraries), CLI, control channel | ✅ |
 | XMP sidecars (read/write, auto-write), reading `crs:` develop settings, preset files (`.lcpreset`, XMP presets) | ✅ |
-| Optics (distortion, vignetting, auto + manual CA, defringe, DNG-embedded lens corrections), Geometry (transforms, Constrain Crop), Upright (Auto/Level/Vertical/Full/Guided) | ✅ · camera lens profiles (our own) ⬜ |
+| Optics (distortion, vignetting, auto + manual CA, defringe, lens corrections embedded in DNG files and Panasonic / Leica RW2 / RWL distortion data), Geometry (transforms, Constrain Crop), Upright (Auto/Level/Vertical/Full/Guided) | ✅ · camera lens profiles (our own) ⬜ |
 | Photo Merge: HDR (auto-align, deghost), Panorama (spherical/cylindrical/perspective, boundary warp, auto crop), HDR Panorama → DNG | ✅ |
 | GPU pipeline (wgpu compute, CPU-exact within 1/255), CPU fallback on device limits / errors | ✅ · WebGPU in the browser 🚧 |
 | AI: segmentation masks, AI denoise, super resolution, faces; HDR editing; video | ⬜ (see [roadmap](ROADMAP.md#where-were-going)) |
@@ -334,9 +335,68 @@ cargo run --release -p lightcraft-cli -- render photo.jpg -o out.jpg --set light
 cargo xtask ci                                          # fmt, clippy, tests, layering, wasm checks
 ```

+CI defaults to line-table debug information and one build job per 1.5 GB of RAM
+available when it starts (at most one per CPU; 4 if memory can't be read), so an
+8 GB machine with 6 GB free builds with 4, and a busy machine with little free
+builds with fewer. Test threads follow, capped at 4. Full-debuginfo linkers, one
+per CPU, otherwise exhaust RAM before any test runs. GPU coverage is unchanged. Explicit
+`CARGO_PROFILE_DEV_DEBUG`, `CARGO_BUILD_JOBS` and `RUST_TEST_THREADS` settings
+override these defaults. Ordinary development commands keep their own settings.
+
+**Chinese and Japanese text** need the shared font repo, an optional build input (official releases always include it):
+
+```sh
+git clone https://github.com/storytold/craft-fonts ../craft-fonts
+CRAFT_FONTS_DIR=../craft-fonts cargo run --release -p lightcraft
+```
+
+Without it LightCraft builds and runs the same, but Chinese and Japanese text have no glyphs. Fonts are never committed to this
+repo; see [craftrules `standards/fonts.md`](https://github.com/storytold/craftrules/blob/main/standards/fonts.md).
+
+**Interface language:** **Edit → Language** (English, 简体中文, 繁體中文（台灣）, 日本語, Português (Brasil), Deutsch) or **Settings → General →
+Language**; the choice applies immediately and persists. See [docs/localization.md](docs/localization.md).
+
+**Logs:** the desktop app writes its log to standard error and to `logs/lightcraft.log` in its settings folder
+(Linux `$XDG_CONFIG_HOME/lightcraft/logs/`, by default `~/.config/lightcraft/logs/`; macOS
+`~/Library/Application Support/LightCraft/logs/`; Windows `%APPDATA%\LightCraft\logs\`), never in the library. A
+launch from a desktop menu or the Dock has no terminal, so attach this file to a bug report. Each start moves the
+previous log to `lightcraft.1.log` and that one to `lightcraft.2.log`, so the log of a run that crashed survives the
+next start; the file stops growing at 16 MiB, `--version` and `--help` write none, and runs with
+`LIGHTCRAFT_NO_PREFS` log to standard error only. By default LightCraft's own crates log at `info` and everything else
+at `warn`. `LIGHTCRAFT_LOG=info` or `debug` works as before (that level for LightCraft's own crates, warnings and
+errors from the rest; any other value: warnings and errors only) and wins over `RUST_LOG`, which otherwise replaces
+the default with env_logger-style directives such as `RUST_LOG=debug` or `RUST_LOG=warn,lightcraft_pipeline=trace` (a
+directive ending in `*` covers every target starting with it, as in `lightcraft*=debug`). Panics are recorded there
+too, and still in `lightcraft-panics.log` in the temp folder. The logger is `apps/lightcraft/src/logging.rs`.
+
 The web build needs the `wasm32-unknown-unknown` target and the matching `wasm-bindgen` CLI
 (`cargo xtask web` prints the exact install command); see [docs/web.md](docs/web.md).

+**Nix** builds the desktop app and `lightcraft-cli` (the Nix build always includes the craft-fonts input, so Japanese
+text has glyphs):
+
+```sh
+nix run github:storytold/lightcraft                    # the desktop app
+nix build github:storytold/lightcraft                  # → ./result/bin/{lightcraft,lightcraft-cli}
+nix develop github:storytold/lightcraft                # rust toolchain + native deps + fonts
+```
+
+In a flake configuration (NixOS, home-manager, nix-darwin):
+
+```nix
+# flake.nix
+inputs.lightcraft.url = "github:storytold/lightcraft";
+# optional: build against your own nixpkgs instead of the one LightCraft pins
+# inputs.lightcraft.inputs.nixpkgs.follows = "nixpkgs";
+
+# then, in a NixOS or home-manager module (where `inputs` is in scope):
+nixpkgs.overlays = [ inputs.lightcraft.overlays.default ];   # makes `pkgs.lightcraft` available
+environment.systemPackages = [ pkgs.lightcraft ];           # home-manager: home.packages = [ pkgs.lightcraft ];
+```
+
+`nix build` installs the same desktop file, hicolor icons and AppStream metadata as the .deb/.rpm, and runs
+`cargo test --workspace` as its check phase (skip it with `pkgs.lightcraft.overrideAttrs { doCheck = false; }`).
+
 **Keyboard:** <kbd>G</kbd> grid · <kbd>D</kbd> detail · <kbd>E</kbd> edit · <kbd>C</kbd> crop · <kbd>M</kbd> masking ·
 <kbd>Shift</kbd>+<kbd>P</kbd> presets · <kbd>\\</kbd> original · <kbd>Y</kbd> before/after · <kbd>Z</kbd> zoom ·
 <kbd>J</kbd> clipping · <kbd>⌘Z</kbd> undo · <kbd>⌘/</kbd> all shortcuts.
@@ -356,7 +416,8 @@ Humans and agents follow the same rules, so read [AGENTS.md](AGENTS.md) first. T
  work from public specs and black-box observation.
 - **No Adobe assets, ever:** no icons, screenshots, presets, profiles, LUTs or fonts from Adobe products. Every
  image, icon and font in the repo is original, public domain, Creative Commons, OFL or permissively licensed, and has
-  an entry in [assets/ATTRIBUTION.md](assets/ATTRIBUTION.md) added in the same commit.
+  an entry in [assets/ATTRIBUTION.md](assets/ATTRIBUTION.md) added in the same commit. New fonts go to
+  [storytold/craft-fonts](https://github.com/storytold/craft-fonts), not here.
 - **Pure Rust**, enforced crate layering, everything is a command, and `cargo xtask ci` green before every commit
  (one task id per commit).
 - **Never crash.** Non-test code returns errors instead of panicking: no `unwrap()`, `expect()`, `panic!` or
@@ -367,6 +428,53 @@ Questions, ideas or a bug you'd like to talk through first? Bring them to [Disco

 <br>

+## Downloads
+
+**New to LightCraft?** Download it from the [LightCraft page on getartcraft.com](https://getartcraft.com/apps/lightcraft). That's the easiest way to install it.
+
+**Want a specific build or format?** On GitHub, the [latest release](https://github.com/storytold/lightcraft/releases/latest) has every build listed below, and [all releases](https://github.com/storytold/lightcraft/releases) has earlier versions and their notes. `<ver>` in the file names is the version number, and `SHA256SUMS.txt` lists a checksum for every file.
+
+### Windows
+
+| Build | Installer | Portable |
+|---|---|---|
+| x64 (64-bit Intel/AMD) | `lightcraft-<ver>-windows-x64.msi` | `lightcraft-<ver>-windows-x64-portable.zip` |
+| arm64 (Snapdragon and other ARM PCs) | `lightcraft-<ver>-windows-arm64.msi` | `lightcraft-<ver>-windows-arm64-portable.zip` |
+| x86 (32-bit) | `lightcraft-<ver>-windows-x86.msi` | `lightcraft-<ver>-windows-x86-portable.zip` |
+
+Installers and executables are code-signed.
+
+### macOS
+
+| Build | File | Notes |
+|---|---|---|
+| App, universal (Apple silicon + Intel) | `lightcraft-<ver>-macos-universal.dmg` | Signed and notarized |
+| Command-line tool, universal | `lightcraft-cli-<ver>-macos-universal.zip` | Signed and notarized |
+
+### Linux
+
+| Format | x86_64 | aarch64 (ARM64) | Notes |
+|---|---|---|---|
+| AppImage | `lightcraft-<ver>-linux-x86_64.AppImage` | `lightcraft-<ver>-linux-aarch64.AppImage` | Runs anywhere; updates itself with [AppImageUpdate](https://github.com/AppImageCommunity/AppImageUpdate) (`.zsync` files) |
+| Flatpak | `lightcraft-<ver>-linux-x86_64.flatpak` | `lightcraft-<ver>-linux-aarch64.flatpak` | Sandboxed; `flatpak install --user <file>` |
+| Debian/Ubuntu | `lightcraft-<ver>-linux-x86_64.deb` | `lightcraft-<ver>-linux-aarch64.deb` | |
+| Fedora/RHEL/openSUSE | `lightcraft-<ver>-linux-x86_64.rpm` | `lightcraft-<ver>-linux-aarch64.rpm` | |
+| Tarball | `lightcraft-<ver>-linux-x86_64.tar.gz` | `lightcraft-<ver>-linux-aarch64.tar.gz` | Unpack anywhere |
+
+### FreeBSD
+
+| Build | File |
+|---|---|
+| x86_64 | `lightcraft-<ver>-freebsd-x86_64.tar.gz` |
+
+### Web (WebAssembly)
+
+| Build | File | Notes |
+|---|---|---|
+| Static site | `lightcraft-web-<ver>.zip` | Runs in a modern browser; host it on any static server |
+
+<br>
+
 ## The Crafting Apps

 LightCraft is one of the **Crafting Apps**: free, open-source creative tools from the
@@ -379,7 +487,7 @@ stand on its own.
 | <img src="https://raw.githubusercontent.com/storytold/vectorcraft/main/assets/app-icon/hicolor/64x64/apps/ai.storyteller.vectorcraft.png" alt="" width="32" height="32"> | **VectorCraft** | Vector illustration | [GitHub](https://github.com/storytold/vectorcraft) | [Website](https://getartcraft.com/apps/vectorcraft) |
 | <img src="https://raw.githubusercontent.com/storytold/filmcraft/main/assets/app-icon/hicolor/64x64/apps/ai.storyteller.filmcraft.png" alt="" width="32" height="32"> | **FilmCraft** | Video editing, color and sound | [GitHub](https://github.com/storytold/filmcraft) | [Website](https://getartcraft.com/apps/filmcraft) |
 | <img src="https://raw.githubusercontent.com/storytold/lightcraft/main/assets/app-icon/hicolor/64x64/apps/ai.storyteller.lightcraft.png" alt="" width="32" height="32"> | **LightCraft** | **Photo library and raw development · you are here** | [GitHub](https://github.com/storytold/lightcraft) | [Website](https://getartcraft.com/apps/lightcraft) |
-| <img src="https://raw.githubusercontent.com/storytold/printcraft/main/assets/app-icon/hicolor/64x64/apps/ai.storyteller.printcraft.png" alt="" width="32" height="32"> | **PrintCraft** | Reading, organizing and protecting PDFs | [GitHub](https://github.com/storytold/printcraft) | [Website](https://getartcraft.com/apps/printcraft) |
+| <img src="https://raw.githubusercontent.com/storytold/pdfcraft/main/assets/app-icon/hicolor/64x64/apps/ai.storyteller.pdfcraft.png" alt="" width="32" height="32"> | **PdfCraft** | Reading, organizing and protecting PDFs | [GitHub](https://github.com/storytold/pdfcraft) | [Website](https://getartcraft.com/apps/pdfcraft) |
 | <img src="https://raw.githubusercontent.com/storytold/effectcraft/main/assets/app-icon/hicolor/64x64/apps/ai.storyteller.effectcraft.png" alt="" width="32" height="32"> | **EffectCraft** | Motion graphics and visual effects | [GitHub](https://github.com/storytold/effectcraft) | [Website](https://getartcraft.com/apps/effectcraft) |
 | <img src="https://raw.githubusercontent.com/storytold/designcraft/main/assets/app-icon/hicolor/64x64/apps/ai.storyteller.designcraft.png" alt="" width="32" height="32"> | **DesignCraft** | Page layout and publishing | [GitHub](https://github.com/storytold/designcraft) | [Website](https://getartcraft.com/apps/designcraft) |

@@ -420,7 +528,9 @@ with its author, source and license in [assets/ATTRIBUTION.md](assets/ATTRIBUTIO
 Showcase photographs are public-domain works, used via Wikimedia Commons: Ansel Adams, *The Tetons and the Snake River*
 (1942, U.S. National Archives); Dorothea Lange, *Migrant Mother* (1936, Library of Congress); Bill Anders / NASA,
 *Earthrise* (1968); NASA, *The Blue Marble* (1972). The demo library is procedurally generated by LightCraft. UI font:
-Inter (SIL OFL 1.1). All icons are original.
+Inter (SIL OFL 1.1). Builds made with [craft-fonts](https://github.com/storytold/craft-fonts) (all official releases)
+also embed its Chinese and Japanese fonts (Noto Sans CJK SC, BIZ UDPGothic, BIZ UDMincho, Shippori Mincho; SIL OFL 1.1), listed in its
+[ATTRIBUTION.md](https://github.com/storytold/craft-fonts/blob/main/ATTRIBUTION.md). All icons are original.

 The ArtCraft name, wordmark and logos in [`docs/brand/`](docs/brand/) are trademarks of the
 ArtCraft Team and are not covered by this license. They may be used only unmodified, and only as
@@ -433,3 +543,7 @@ Forks and modified versions must remove them.
  <a href="https://getartcraft.com/"><img alt="ArtCraft" src="docs/brand/artcraft-mark.svg" width="28"></a><br>
  <sub>Made by the <a href="https://getartcraft.com/">ArtCraft</a> team and community.</sub>
 </p>
+
+## Star history
+
+[![Star History Chart](https://api.star-history.com/svg?repos=storytold/lightcraft&type=Date&legend=top-left)](https://www.star-history.com/?repos=storytold%2Flightcraft&type=date&legend=top-left)
@@ -6,11 +6,11 @@ projects (DrawCraft reached its first four milestones in ≈ 4½ h) and are revi

 ## Where we stand

-*Honest assessment, 2026-10-05. Agents: read this before picking work. The checklist in
+*Honest assessment, 2026-10-08. Agents: read this before picking work. The checklist in
 [`docs/parity.md`](docs/parity.md) counts features that **exist**; this section is about whether a photographer can
 **switch** from Lightroom. Update it when a gap below closes.*

-**In one line:** the checklist says **79%** (P0 98.5%, P1 95.9%, P2 39%), but measured by whether a working
+**In one line:** the checklist says **79.7%** (P0 98.2%, P1 95.6%, P2 41.6%), but measured by whether a working
 photographer could replace Lightroom without noticing, we are at roughly **60–70%**. The remaining gap is mostly
 **quality of results and camera coverage**, not missing buttons.

@@ -22,32 +22,34 @@ duplicate Local entries #22, black GPU exports on an Intel iGPU #78).

 | Dimension | Estimate | What's true today | Biggest gaps |
 |---|---:|---|---|
-| **Feature checklist** | 79% | P0 core and P1 nearly complete: import (Add / Copy / Move, templates, devices), library, grid/loupe/compare/survey, every Edit slider, curves, colour grading, masking tools, crop/Upright, heal/clone, presets/profiles, versions/history, sync, export, menus, shortcuts | P1: lens-profile database, content-aware fill (patch synthesis), video playback/trim |
-| **RAW coverage** (formats people shoot) | ~50% | DNG (all kinds), CR2, ARW, NEF (uncompressed + Huffman lossless/lossy), uncompressed RAF/ORF, packed RW2, PEF; every container's embedded preview (incl. CR3) | **CR3** (every Canon since ~2018), compressed RAF/ORF, RW2 v4, Nikon lossy-after-split, Canon sRAW, HEIC/AVIF. Per-model verification is thin (~40 corpus files vs >1,000 models) |
-| **Colour & image quality** | ~55–65% | Pipeline is complete and fast; GPU path CPU-exact within 1/255 | **No camera colour calibration**: non-DNG raws use a neutral matrix, so colour is muted/inaccurate. No lens-profile database. No measured fidelity against Lightroom (tone, highlights, texture/clarity, NR, sharpening are tuned by eye) |
+| **Feature checklist** | 79.7% | P0 core and P1 nearly complete: import (Add / Copy / Move, templates, devices), library, grid/loupe/compare/survey, every Edit slider, curves, colour grading, masking tools, crop/Upright, heal/clone, presets/profiles, versions/history, sync, export, menus, shortcuts | P0: full-resolution zoom detail; P1: lens-profile database, content-aware fill (patch synthesis), video playback/trim |
+| **RAW coverage** (formats people shoot) | ~55% | DNG (all kinds), CR2, CR3 lossless Bayer and version 0x100/0x200 C-RAW (M50/R100/R8 pixel-exact corpus), ARW, NEF (uncompressed + Huffman lossless/lossy), RAF (uncompressed, lossless/lossy compressed Bayer and X-Trans), uncompressed ORF, RW2 / RWL / Panasonic RAW (every raw format, checked on 178 files from 118 Panasonic and Leica bodies), PEF; every container's embedded preview (incl. CR3) | **CR3** (every Canon since ~2018), compressed ORF, Nikon lossy-after-split, Canon sRAW, HEIC/AVIF. NEFs labelled compressed but stored uncompressed (Z 6 packed 14-bit, D850 12-bit uncompressed). Per-model verification is thin (~55 corpus files vs >1,000 models) |
+| **Colour & image quality** | ~55–65% | Pipeline is complete and fast; GPU path CPU-exact within 1/255 | **No measured camera calibration database**: ARW, NEF, RW2, RAF and CR3 have guarded camera-JPEG colour estimates, with bundled ILCE-7M4, X-H2S and X-T4 profiles (docs/camera-preview-colour.md); other non-DNG raws and rejected estimates use a neutral matrix. Colour fidelity remains incomplete. No lens-profile database. No measured fidelity against Lightroom (tone, highlights, texture/clarity, NR, sharpening are tuned by eye) |
 | **AI & computational** | ~15–20% | Assisted culling (focus, bursts), auto tone, HDR/panorama merge; subject/sky/background masks as classical heuristics | Real segmentation masks (subject, sky, people, objects, landscape, depth), AI denoise, super resolution, lens blur, generative remove, faces/people, natural-language search. **Blocked on a model strategy** (licensable weights or our own training; pure-Rust inference is feasible) |
 | **Workflow & library** | ~85% (single machine) | Robust catalog (journal + snapshots, background compaction, crash-tested), 85k-photo libraries stay responsive, Local browsing with automatic cleanup, XMP interop, keywords, smart albums, Move import | Opening an 85k library takes 1.7–4.7 s; no cloud sync (out of scope), no tablet companion (#74, roadmap), shared albums, publish services, tethering |
 | **Classic modules** | ~30% | Geotagging from GPX track logs, soft proofing (partial), slideshow (basic) | **Map view, Book, Print, Slideshow module, Web, publish services**: ~40 tracker rows ⬜ |
 | **HDR & video** | 0% | | HDR edit/display/export; video play/trim/edit/export |
-| **Platform & robustness** | ~70% | macOS native; Windows/Linux builds; web via WASM; no-panic lints workspace-wide, `unsafe` confined to `crates/sysmem`; failed saves are reported; GPU errors fall back to CPU | Windows installer UI unverified on Windows (PR #79); GPU path proven only on Apple + user reports; no localisation; accessibility partial; headless UI tests time out under machine load |
+| **Platform & robustness** | ~70% | macOS native; Windows/Linux builds; web via WASM; no-panic lints workspace-wide, `unsafe` confined to `crates/sysmem`; failed saves are reported; GPU errors fall back to CPU | Windows installer UI unverified on Windows (PR #79); GPU path proven only on Apple + user reports; English, Simplified/Traditional Chinese, Japanese, Brazilian Portuguese and German UI (see docs/localization.md); remaining technical errors; Traditional Chinese uses the Simplified Chinese font until craft-fonts has a TC face; accessibility partial; headless UI tests time out under machine load |

 ### By kind of user

 | User | Readiness | What blocks them |
 |---|---:|---|
 | JPEG / DNG shooter, single machine | ~85% | Fidelity polish, AI masks |
-| Nikon / Sony / older-Canon raw shooter | ~65% | Camera colour (muted colour on every photo) |
-| Canon CR3 / Fujifilm / Olympus shooter | ~35% | Their raws open as embedded previews only |
+| Nikon / Sony / Panasonic / older-Canon raw shooter | ~65% | Camera colour fidelity and coverage (ARW, NEF and RW2 preview estimates are only a starting point); Panasonic compacts and kit zooms also miss their embedded distortion correction |
+| Fujifilm raw shooter | ~65% | Uncompressed and lossless/lossy compressed RAF decoded; camera colour calibration remains missing. Verified on 13 bodies, including 14/16-bit GFX; see `docs/raf-compression.md` |
+| Canon CR3 / Olympus compressed-raw shooter | ~45% | CR3 lossless Bayer and version 0x100/0x200 C-RAW develop from sensor data (M50, R100, R8 verified pixel for pixel); other CRX variants and compressed ORF open as embedded JPEG previews. Camera colour and broader model verification remain |
 | Lightroom Classic power user | ~45% | Print, Book, Map, publish, tethering |
-| Relies on AI (masks, denoise) | ~25% | No segmentation or AI denoise models |
+| Relies on AI (masks, denoise) | ~25% | Object / Describe masks via optional SAM 3 (download not yet hosted); no AI denoise |

 ## Where we're going

 Priorities, in order. Each points at tracker rows in [`docs/parity.md`](docs/parity.md) → *Top gaps*.

 1. **Camera colour calibration of our own** (LR-PROF-CAMERACOLOR, P0): fit each camera to its own embedded JPEG, use
-   matrices the files carry themselves, then chart shots. Raises colour quality for every non-DNG raw at once.
-2. **Raw formats, clean-room** (LR-IMP-FORMATS, P0): **CR3** first, then compressed RAF / ORF, RW2 v4, NEF
+   matrices the files carry themselves, then chart shots. Sony ARW, Nikon NEF, Panasonic RW2 and Fujifilm RAF have the file-local fit
+   (matrix + tone curve from their own JPEG); generalise it to the other makes' raws (PEF, ORF…), then validate fidelity.
+2. **Raw formats, clean-room** (LR-IMP-FORMATS, P0): Remaining **unverified CR3 CRX** variants, compressed ORF, NEF
   lossy-after-split, sRAW. Decided 2026-10-05: write our own decoders from prose descriptions (never decoder source,
   no LGPL dependency); compressed NEF (#86) is the template.
 3. **Verified camera coverage** (LR-IMP-CAMERA-COVERAGE, P0): a CC0 sample per model in the corpus, each decoded and
@@ -56,7 +58,9 @@ Priorities, in order. Each points at tracker rows in [`docs/parity.md`](docs/par
   (references stay in the local `plan/`), then tune against the numbers.
 5. **Lens profiles of our own** (LR-EDIT-OPTICS-PROFILE, P1).
 6. **AI model strategy** (maintainer decision): which permissively licensed models (or our own training) for
-   segmentation masks and denoise; then pure-Rust inference. Unblocks M12 and Enhance.
+   segmentation masks and denoise; then pure-Rust inference. Unblocks M12 and Enhance. Object / Describe masks now
+   run Meta's SAM 3 in pure Rust (optional, user-consented download under the non-OSI SAM License; CDN mirrors still
+   to be set up, docs/ai-masks.md); Subject / Sky / People and Enhance are still open.
 7. **Then:** HDR (Q), the Classic output modules (Print first, then Map view, Book, Slideshow), video (R), localisation
   and accessibility.

@@ -64,6 +68,10 @@ Already closed in the week of 2026-10-03: compressed NEF (#10), Move import (#29
 Local roots / cleanup, grid and catalog performance at 85k photos (#35, #37), failed-save reporting, GPU export
 hardening (#78), copyright metadata (#51), GPX geotagging (#60), import tag help and folder templates (#31, #32).

+Image navigation now supports native pinch zoom and two-finger pan in Detail, Compare and Reference views.
+The whole-image preview still has a configurable size cap (2,560 px default), so 100% on larger photos does not
+yet guarantee original-pixel detail; visible-region rendering remains a gap (LR-VIEW-ZOOM).
+
 ## Milestones

 **Status legend:** ✅ done · 🚧 in progress · ⬜ not started
@@ -81,24 +89,24 @@ hardening (#78), copyright metadata (#51), GPX geotagging (#60), import tag help
 | M8 | Heal / Remove | content-aware remove (PatchMatch), heal, clone, brush spots, visualize spots, red/pet eye | 6–10 | 🚧 (heal, clone, auto source, visualize spots, red/pet eye ✅; PatchMatch remove ⬜) |
 | M9 | Presets, profiles, versions, sync | preset browser + amount, create/import presets, profile browser, versions, history, copy/paste/sync settings | 5–8 | ✅ |
 | M10 | Export & share | export dialog (JPEG/PNG/TIFF/DNG/AVIF/JXL/original), sizing, sharpening, metadata, watermark, naming, batch jobs, XMP sidecars, HDR export | 6–10 | 🚧 (all formats incl. DNG/original, sizing, presets, background jobs ✅; JXL encode, HDR export ⬜) |
-| M11 | RAW II | CR3, RAF (X-Trans), ORF, RW2, PEF, SRW, 3FR, IIQ + long tail; camera calibration DB; HEIC/AVIF/JXL import | 20–35 | 🚧 (RAF uncompressed, RW2 packed, PEF, ORF uncompressed ✅; **camera colour calibration** ⬜ (top priority), CR3, compressed ORF/RAF ⬜) |
+| M11 | RAW II | CR3, RAF (X-Trans), ORF, RW2, PEF, SRW, 3FR, IIQ + long tail; camera calibration DB; HEIC/AVIF/JXL import | 20–35 | 🚧 (CR3 lossless CRX and C-RAW, RAF uncompressed and lossless/lossy compressed, RW2 (every raw format), PEF, ORF uncompressed ✅; **camera colour calibration** 🚧 (guarded ARW, NEF, RW2 and RAF preview fitting; measured database still missing), CR3, compressed ORF ⬜) |
 | M12 | AI & smart features | subject/sky/background/people/object masks, semantic search, faces/People (permissively licensed models, pure-Rust inference) | 20–40 | ⬜ |
 | M13 | Merge | HDR merge (deghost), panorama (projections, boundary warp, fill edges), HDR panorama | 10–15 | ✅ |
 | M14 | Video | import/playback/trim via FilmCraft crates, global edits + presets on video, video export | 6–10 | ⬜ |
 | M15 | Classic modules | Map, Book, Slideshow, Print, Web; smart collections, stacks, virtual copies, publish services, tethering | 25–40 | 🚧 (smart albums, stacks, virtual copies, compare/survey ✅; Map/Book/Slideshow/Print/Web ⬜) |
-| M16 | 1.0 polish | preferences, shortcut editor, accessibility, localization, packaging (dmg/msi/AppImage/web), hardening | 10–20 | 🚧 (settings, keyboard shortcuts sheet, packaging basics ✅; accessibility, localisation ⬜) |
+| M16 | 1.0 polish | preferences, shortcut editor, accessibility, localization, packaging (dmg/msi/AppImage/web), hardening | 10–20 | 🚧 (settings, keyboard shortcuts sheet, packaging basics ✅; English/Chinese (Simplified, Traditional)/Japanese/Brazilian Portuguese/German localisation 🟡; accessibility and further locales ⬜) |

-## Parity estimate (feature count updated 2026-10-05; effort estimate from 2026-10-02)
+## Parity estimate (feature count updated 2026-10-08; effort estimate from 2026-10-02)

 **By feature count** — from `docs/parity.md` (one row per Lightroom feature, menu item and shortcut; `cargo xtask
 parity` prints this line on every run, so it stays current):

 | Scope | Weighted completion | Rows | 2026-10-02 |
 |---|---:|---:|---:|
-| P0 (core) | **98.5%** | 200 | 98.7% |
-| P1 (important parity) | **95.9%** | 147 | 94.4% |
-| P2 (later / AI / niche, incl. Classic modules) | **39.2%** | 158 | 29.4% |
-| **All in-scope rows** | **79.2%** | 505 | 75.6% |
+| P0 (core) | **98.2%** | 200 | 98.7% |
+| P1 (important parity) | **95.6%** | 149 | 94.4% |
+| P2 (later / AI / niche, incl. Classic modules) | **41.6%** | 160 | 29.4% |
+| **All in-scope rows** | **79.7%** | 509 | 75.6% |

 The 2026-10-05 count includes three new 🟡 rows that make quality gaps visible (camera colour calibration, verified
 camera coverage, render fidelity), which is why P0 dipped slightly.
@@ -115,7 +123,7 @@ trip, slideshow, auto import…) in ≈ 12 h on 2026-10-02; four to six parallel
 | Work package | Tracker rows | Agent-hours | Risk |
 |---|---|---:|---|
 | Remaining P0/P1 UI and library features (folder rename/move, keyword painter, people view…) | ≈ 8 | 5–10 | low |
-| Raw codecs: CR3 (CRX), compressed ORF / RAF, NEF lossy-after-split, RW2 v4, HEIC/AVIF decode, JPEG XL DNG | LR-IMP-FORMATS | 40–80 | **high** — clean-room black-box analysis, no permissive specs |
+| Raw codecs: CR3 (CRX), compressed ORF, NEF lossy-after-split, HEIC/AVIF decode, JPEG XL DNG | LR-IMP-FORMATS | 40–80 | **high** — clean-room black-box analysis, no permissive specs |
 | Lens-profile database of our own (calibration targets, fitting, data) | LR-EDIT-OPTICS-PROFILE | 15–30 | data collection |
 | Video: playback, trim, edits, export (pure-Rust decode, ideally shared with FilmCraft) | R. Video | 20–40 | medium |
 | AI: subject / sky / background / people / object masks, object-aware remove, AI denoise, super resolution, lens blur, people & faces, natural-language search, culling | ≈ 30 | 80–150 | **high** — permissively licensed weights, pure-Rust inference, maybe training |
@@ -159,42 +167,66 @@ The milestone estimates in the table above were made before work started and are

 ## Raw format coverage and known gaps

+Sony ILCE-7M4 downsized lossless ARW (subsampled YCbCr 4:2:0 / 4:2:2 tiles) now decodes to linear RGB;
+private 3:2 & 4:3 examples verified through native rendering & full-resolution 16-bit export.
+
+CR3 lossless Bayer and version 0x100/0x200 C-RAW sensor decoding is verified pixel-exactly on Canon M50, R100 and R8; any other CR3, or one that fails to decode, opens from its embedded JPEG as before. See [`docs/cr3.md`](docs/cr3.md) for coding limits, reference provenance and colour limitations.
+
 Decoded (CC0 corpus from raw.pixls.us, `cargo xtask corpus --download`, `crates/raw/tests/corpus.rs`): DNG (uncompressed,
-LJ92, lossy JPEG / Smart Previews, Deflate, float, linear), CR2, ARW (uncompressed, ARW2, LJ92), NEF/NRW uncompressed and Huffman-compressed (lossless, lossy type 1/2, 12/14-bit), RAF uncompressed (Bayer and
-X-Trans), RW2 packed 12/14-bit, PEF (uncompressed and Huffman), ORF uncompressed (16-bit and 12-bit packed). Every
-supported container also yields its embedded JPEG preview (CR3 too), and the engine shows that preview for raw variants
-it can't decode yet.
+LJ92, lossy JPEG / Smart Previews, Deflate, float, linear), CR2, ARW (uncompressed, ARW2, LJ92; as-shot white balance and black level of pre-2017 bodies from the enciphered
+maker-note `Tag2010` and the encrypted `SR2SubIFD`, both recovered by black-box analysis, `crates/raw/src/vendor/arw.rs`), NEF/NRW uncompressed and Huffman-compressed (lossless, lossy type 1/2, 12/14-bit), RAF uncompressed and lossless/lossy compressed (Bayer and
+X-Trans, 14/16-bit real-file verification), RW2 / Leica RWL / Panasonic RAW in every raw format (compressed formats 4 and 6, the prefix-coded strips of format 8,
+packed formats 2, 5 and 7, the 16-bit words of the 2005–2007 bodies; all recovered by black-box analysis of 178 CC0 files from
+118 bodies, `crates/raw/src/vendor/rw2.rs`), PEF (uncompressed and Huffman), ORF uncompressed (16-bit and 12-bit packed). Supported containers yield their embedded JPEG preview when present (including CR3). The engine uses it for RAW variants it cannot decode yet; HEVC-only CR3 previews are not decoded.

 Not decoded yet — preview only (no permissively licensed description; black-box analysis incomplete):
 - **Nikon "lossy after split" NEF** (non-zero split row in maker note `0x0096`, e.g. some D3400/D5000/D5200/D5500/D5600
  files): rows above the split decode with the regular lossy table; from the split row on a different code is used
  that our black-box analysis has not recovered yet (none of the four regular tables fits, also not with byte
  alignment or reset predictors at the split row). The other Nikon Huffman variants are decoded (`crates/raw/src/vendor/nefc.rs` documents the analysis).
- **Panasonic RW2 raw format 4** (quantised): the block layout is known (0x4000-byte chunks rotated by 0x1ff8; 128-bit
-  blocks of two 12-bit seeds plus four groups of a 2-bit scale and three 8-bit codes; scales 0/1 are ×1/×2 differences
-  from the same-colour pixel two to the left), the reconstruction rule for scales 2/3 is not established.
- **Olympus compressed ORF**, **Fujifilm compressed RAF**, **Canon CR3/CRX** (M11.1), **Canon sRAW/mRAW**, lossy DNG.
+- **Olympus compressed ORF**, **Canon CR3 unverified CRX variants** (M11.1), **Canon sRAW/mRAW**, lossy DNG.

-**Camera colour matrices:** non-DNG raws use the documented neutral fallback (camera RGB ≈ linear sRGB, flagged
+**Camera colour matrices:** ARW, NEF, RW2, RAF and CR3 files can use guarded, separate chromaticity and tone estimates from their own embedded JPEG (see `docs/camera-preview-colour.md`); this is a per-file camera-look estimate with relative WB, not measured calibration or absolute-Kelvin WB. Other non-DNG raws and rejected fits use the documented neutral fallback (camera RGB ≈ linear sRGB, flagged
 `matrix_is_fallback`) with the file's as-shot white-balance multipliers. Clean sources to evaluate next: manufacturer
-matrices stored in the files themselves (Olympus ImageProcessing `ColorMatrix`, Pentax/Panasonic equivalents) and our
+matrices stored in the files themselves (Olympus ImageProcessing `ColorMatrix`, Pentax equivalents; Panasonic RW2 files carry none) and our
 own chart-based calibration (M11.4). Adobe matrices are never used.

+## Lightroom Classic catalog migration
+
+File → Import Lightroom Catalog… reads `.lrcat` plus committed WAL pages directly through a pure-Rust
+SQLite reader. Originals stay in place; ratings, flags, labels, XMP metadata, hierarchical keywords,
+collections/sets, virtual copies and supported develop settings migrate into LightCraft. Existing edits
+are preserved by default, reimport identities are persistent, and source settings/history/snapshots are
+archived before catalog mutation. Missing originals remain available for relinking.
+
+Rendering is approximate: unsupported Adobe profiles/AI/process settings are reported and archived;
+history/snapshots remain source data, and smart collections import current membership. The Lightroom
+database is read-only; LightCraft owns subsequent edits. See `docs/lightroom-catalog-import.md`.
+
 ## Log
 - 2026-09-30: roadmap created; M0 in progress; research docs (Lightroom reference, Rust imaging ecosystem) complete.
 - 2026-09-30 (later): app running with the full Lightroom-style UI; pipeline v0; DNG/CR2/ARW; README showcase. ≈ 8 h elapsed.
 - 2026-10-02: parity estimate added (xtask parity prints weighted completion); milestone statuses refreshed.
+- 2026-10-08: Fujifilm camera colour: guarded JPEG matching and relative WB, plus bundled X-H2S/X-T4 profiles from 201/545 photos. On 150 withheld files the pooled profiles improve mean ΔE slightly over per-file fitting (X-H2S 1.70 → 1.62, X-T4 2.43 → 2.34); dark X-H2S samples 8.74 → 2.25. Measured calibration remains open.
+- 2026-10-08: Fujifilm lossless/lossy compressed RAF: pure-Rust striped decoder; full sensor arrays verified against a black-box reference on 17 CC0 files and 7 supplied X-H2S / X-T4 files (13 camera bodies, 14/16-bit Bayer and X-Trans). Camera colour calibration remains a separate gap.
 - 2026-10-01: RAW II formats: RAF (uncompressed Bayer + X-Trans), RW2 (packed), PEF (incl. Huffman), ORF (uncompressed); embedded previews for every container incl. CR3; raw corpus test with 37 CC0 samples.
 - 2026-10-03 – 10-05: community PRs (#42–#51, #60) and 25+ issues landed: compressed NEF, Move import, folder templates,
  Local roots and cleanup, 85k-photo grid and catalog performance, background compaction, failed-save errors, GPU
  export hardening, clippy 1.99. Added the honest *Where we stand* assessment and *Where we're going* priorities; added
  tracker rows for camera colour, camera coverage and render fidelity.
+- 2026-10-07: Panasonic RW2 / Leica RWL / Panasonic RAW decode in every raw format (compressed 4/6/8, packed 2/5/7,
+  16-bit words), black levels, in-camera aspect crops and mapped-out defects established on 178 CC0 files from 118
+  bodies; RW2 gets the file-local camera look (accepted on 140 of 174 files with a preview).
+- 2026-10-08: independent Rust CR3 lossless and version 0x100/0x200 C-RAW decoding, six exact full-sensor regressions on M50/R100/R8; any CR3 decode error falls back to the embedded JPEG; guarded CR3 camera-JPEG colour fitting with independent framing validation (`docs/cr3.md`). Unverified CRX variants and broader model verification remain.

-## Japanese interface and text watermarks
+## Chinese and Japanese interfaces, and text watermarks

-English/Japanese interface language is persisted in UI state. Core menus have Japanese
-translations; untranslated panels and dialogs retain English. BIZ UDMincho is bundled
-under OFL for Japanese glyph coverage without system fonts. Text watermarks now accept
+English, Simplified Chinese, Traditional Chinese (Taiwan) and Japanese interface languages are persisted in UI state, and the
+language table (`crates/ui-egui/src/i18n.rs`) drives the menus, settings and fonts, so another
+language is a table entry plus two catalogs (docs/localization.md). Core menus and panels are
+translated; untranslated text retains English. CJK glyphs (Chinese: Noto Sans CJK SC; Japanese UI:
+BIZ UDPGothic; watermarks: BIZ UDMincho) come from storytold/craft-fonts, embedded by builds made
+with the optional `CRAFT_FONTS_DIR` input (all releases), so no system fonts are needed. Text watermarks now accept
 `vertical: true` in export JSON/presets and expose an orientation selector. Japanese
 characters stay upright in top-to-bottom columns, with newlines starting columns to the
 left. This is basic lettering, without tate-chu-yoko, ruby, kinsoku, or general vertical
@@ -9,6 +9,7 @@
 //! lightcraft-cli synth-merge hdr|panorama -o DIR
 //! lightcraft-cli commands [--json]
 //! lightcraft-cli controls [--json]
+//! lightcraft-cli calibrate [--max N] [--out DIR] FOLDERS/FILES…
 //! ```
 #![forbid(unsafe_code)]
 #![deny(clippy::unwrap_used, clippy::expect_used, clippy::panic, clippy::unimplemented, clippy::todo, clippy::unreachable)]
@@ -70,6 +71,8 @@ USAGE:
                          per line: {\"method\": \"ui.set\", \"params\": {\"view\": \"detail\"}}.
                          Replies go to stdout. `ui.screenshot` without a path writes -o (then
                          OUT-2.png, OUT-3.png…); `ui.settle {timeoutMs?}` waits for renders.
+                          A failed request (\"ok\": false) does not stop the script, but the exit
+                          status is non-zero when any request failed.
        -o, --output OUT  PNG path (a final screenshot is written here if the script took none)
        --size WxH        window size in points (default 1600x1000)
        --scale S         pixels per point (default 1)
@@ -84,6 +87,12 @@ USAGE:
      Write synthetic merge inputs (procedural scene; bracketed DNGs or overlapping PNG views).
  lightcraft-cli commands [--json]   list every command id with its parameters
  lightcraft-cli controls [--json]   list every develop control id with its range
+  lightcraft-cli calibrate [--max N] [--out DIR] FOLDERS/FILES…
+      Fit a colour profile per camera model from raw files and their embedded camera JPEGs
+      (Sony ARW, Nikon NEF, Fujifilm RAF): up to N files spread over the folders (default 300; 0 = all), pooled per
+      model, written as <model>.json to DIR (default: the profiles folder LightCraft reads,
+      <config>/camera-profiles, or $LIGHTCRAFT_CAMERA_PROFILES). Raws of a profiled model then
+      take their colour from the profile and only their tone from their own JPEG.
  lightcraft-cli --version | --help
 ";

@@ -93,6 +102,14 @@ static ALLOC: dhat::Alloc = dhat::Alloc;

 /// Why `--library DIR` can't be opened; for a library open in another program, how to work with
 /// that one instead (issue #99).
+/// Print the open library's warnings (an unlockable library, damaged settings files) on stderr:
+/// stdout carries command results / MCP protocol messages only.
+fn library_warnings(session: &mut Session, who: &str) {
+    for w in session.take_library_warnings() {
+        eprintln!("{who}: warning: {w}");
+    }
+}
+
 fn library_error(dir: &str, e: lightcraft_engine::EngineError) -> String {
    match e {
        lightcraft_engine::EngineError::LibraryInUse(why) => format!(
@@ -115,6 +132,9 @@ fn main() -> ExitCode {
        dhat::Profiler::builder().file_name(file).build()
    };
    alloc_release::install();
+    // Warnings (a GPU render redone on the CPU, an unknown backend name) on stderr; LIGHTCRAFT_LOG
+    // or RUST_LOG picks another level (#168).
+    lightcraft_engine::logging::install("lightcraft-cli");
    let args: Vec<String> = std::env::args().skip(1).collect();
    let r = match args.first().map(String::as_str) {
        Some("run") => run(&args[1..]),
@@ -125,6 +145,7 @@ fn main() -> ExitCode {
        Some("merge") => merge(&args[1..]),
        Some("synth-merge") => synth_merge(&args[1..]),
        Some("controls") => controls(&args[1..]),
+        Some("calibrate") => calibrate(&args[1..]),
        Some("--version" | "-V" | "version") => {
            println!("lightcraft-cli {}", env!("CARGO_PKG_VERSION"));
            Ok(())
@@ -144,6 +165,115 @@ fn main() -> ExitCode {
    }
 }

+/// Raw files below `path` (or `path` itself), skipping hidden and NAS metadata folders.
+fn raw_files(path: &Path, out: &mut Vec<std::path::PathBuf>, depth: usize) {
+    let is_raw =
+        |p: &Path| p.extension().and_then(|e| e.to_str()).is_some_and(|e| ["arw", "nef", "nrw", "raf"].iter().any(|x| e.eq_ignore_ascii_case(x)));
+    if path.is_file() {
+        if is_raw(path) {
+            out.push(path.to_path_buf());
+        }
+        return;
+    }
+    let Ok(entries) = std::fs::read_dir(path) else { return };
+    if depth > 32 {
+        return;
+    }
+    for entry in entries.flatten() {
+        let name = entry.file_name();
+        if name.to_string_lossy().starts_with(['.', '@']) {
+            continue;
+        }
+        raw_files(&entry.path(), out, depth + 1);
+    }
+}
+
+fn calibrate(args: &[String]) -> Result<(), String> {
+    let mut max = 300usize;
+    let mut out: Option<std::path::PathBuf> = None;
+    let mut inputs = Vec::new();
+    let mut i = 0;
+    while i < args.len() {
+        match args[i].as_str() {
+            "--max" => max = take_value(args, &mut i, "--max")?.parse().map_err(|_| "--max needs a number".to_string())?,
+            "--out" => out = Some(take_value(args, &mut i, "--out")?.into()),
+            a if a.starts_with("--") => return Err(format!("unknown option `{a}`")),
+            f => inputs.push(f.to_string()),
+        }
+        i += 1;
+    }
+    if inputs.is_empty() {
+        return Err("calibrate needs folders or raw files".into());
+    }
+    let mut files = Vec::new();
+    for input in &inputs {
+        raw_files(Path::new(input), &mut files, 0);
+    }
+    files.sort();
+    files.dedup();
+    let found = files.len();
+    if max > 0 && files.len() > max {
+        // spread over all folders (dates, scenes) rather than the first N
+        files = (0..max).filter_map(|k| files.get(k * found / max).cloned()).collect();
+    }
+    eprintln!("calibrate: {} of {found} raw files", files.len());
+    let dir = out.or_else(lightcraft_engine::camera_profiles::dir).ok_or("no profiles folder: pass --out DIR")?;
+    let workers = std::thread::available_parallelism().map_or(4, |n| n.get()).clamp(1, 6);
+    let next = std::sync::atomic::AtomicUsize::new(0);
+    let done = std::sync::atomic::AtomicUsize::new(0);
+    let pools: Vec<lightcraft_engine::camera_profiles::Pool> = std::thread::scope(|scope| {
+        let handles: Vec<_> = (0..workers)
+            .map(|_| {
+                scope.spawn(|| {
+                    let mut pool = lightcraft_engine::camera_profiles::Pool::default();
+                    while let Some(path) = files.get(next.fetch_add(1, std::sync::atomic::Ordering::Relaxed)) {
+                        let result = std::fs::read(path).map_err(|e| e.to_string()).and_then(|bytes| pool.add(&bytes));
+                        let n = done.fetch_add(1, std::sync::atomic::Ordering::Relaxed) + 1;
+                        match result {
+                            Ok(Some(model)) => eprintln!("[{n}/{}] {} ({model})", files.len(), path.display()),
+                            Ok(None) => eprintln!("[{n}/{}] {}: skipped (no usable camera JPEG or colour)", files.len(), path.display()),
+                            Err(e) => eprintln!("[{n}/{}] {}: {e}", files.len(), path.display()),
+                        }
+                    }
+                    pool
+                })
+            })
+            .collect();
+        handles.into_iter().filter_map(|h| h.join().ok()).collect()
+    });
+    let mut pool = lightcraft_engine::camera_profiles::Pool::default();
+    for p in pools {
+        pool.merge(p);
+    }
+    let mut written = 0;
+    for result in pool.fit(5) {
+        match result {
+            Ok(profile) => {
+                let path = lightcraft_engine::camera_profiles::save(&profile, &dir)?;
+                println!(
+                    "{}: {} photos, {} colour pairs, hue/saturation table {} → {}",
+                    profile.model,
+                    profile.files,
+                    profile.samples,
+                    profile.hue_sat.is_some(),
+                    path.display()
+                );
+                written += 1;
+            }
+            Err(e) => eprintln!("calibrate: {e}"),
+        }
+    }
+    for (model, n) in pool.files() {
+        if n < 5 {
+            eprintln!("calibrate: {model}: only {n} usable photo(s), at least 5 needed");
+        }
+    }
+    if written == 0 {
+        return Err("no profile written".into());
+    }
+    Ok(())
+}
+
 fn mcp(args: &[String]) -> Result<(), String> {
    let mut connect: Option<String> = None;
    let mut demo = false;
@@ -195,6 +325,7 @@ fn mcp(args: &[String]) -> Result<(), String> {
                    let mut h = Headless::default();
                    let r = h.session.open_library(dir, demo).map_err(|e| library_error(dir, e))?;
                    eprintln!("lightcraft-cli mcp: opened library {dir} ({r:?})");
+                    library_warnings(&mut h.session, "lightcraft-cli mcp");
                    h
                }
                None if demo => Headless::demo(),
@@ -416,39 +547,40 @@ fn run(args: &[String]) -> Result<(), String> {
    if steps.is_empty() {
        return Err("run: no command given (see `lightcraft-cli commands`)".into());
    }
-    let mut backend: Box<dyn Backend> = match connect {
-        Some(addr) => {
-            if demo || library.is_some() || !imports.is_empty() {
-                return Err("--demo, --library and --import apply to headless mode only".into());
-            }
-            Box::new(
-                Remote::connect(&addr)
-                    .map_err(|e| format!("LightCraft is not reachable at {addr} ({e}); start it with `lightcraft --control 7980`"))?,
-            )
-        }
-        None => {
-            let mut h = match &library {
-                Some(dir) => {
-                    let mut h = Headless::default();
-                    h.session.open_library(dir, demo).map_err(|e| library_error(dir, e))?;
-                    h
-                }
-                None if demo => Headless::demo(),
-                None => Headless::default(),
-            };
-            if !imports.is_empty() {
-                let paths = expand_paths(&imports);
-                let r = h.session.execute("library.import", &json!({"paths": paths})).map_err(|e| e.to_string())?;
-                // what follows acts on the imported photos (already-known files are reported as duplicates)
-                let mut ids: Vec<Value> = r["imported"].as_array().cloned().unwrap_or_default();
-                ids.extend(r["duplicates"].as_array().into_iter().flatten().filter_map(|d| d.get("existing").filter(|v| v.is_u64()).cloned()));
-                if let Some(first) = ids.first().cloned() {
-                    h.session.execute("library.select", &json!({"ids": ids, "active": first})).map_err(|e| e.to_string())?;
+    let mut backend: Box<dyn Backend> =
+        match connect {
+            Some(addr) => {
+                if demo || library.is_some() || !imports.is_empty() {
+                    return Err("--demo, --library and --import apply to headless mode only".into());
                }
+                Box::new(Remote::connect(&addr).map_err(|e| {
+                    format!("LightCraft is not reachable at {addr} ({e}); start it with `lightcraft --control {}`", connect_port(&addr))
+                })?)
            }
-            Box::new(h)
-        }
-    };
+            None => {
+                let mut h = match &library {
+                    Some(dir) => {
+                        let mut h = Headless::default();
+                        h.session.open_library(dir, demo).map_err(|e| library_error(dir, e))?;
+                        library_warnings(&mut h.session, "lightcraft-cli");
+                        h
+                    }
+                    None if demo => Headless::demo(),
+                    None => Headless::default(),
+                };
+                if !imports.is_empty() {
+                    let paths = expand_paths(&imports);
+                    let r = h.session.execute("library.import", &json!({"paths": paths})).map_err(|e| e.to_string())?;
+                    // what follows acts on the imported photos (already-known files are reported as duplicates)
+                    let mut ids: Vec<Value> = r["imported"].as_array().cloned().unwrap_or_default();
+                    ids.extend(r["duplicates"].as_array().into_iter().flatten().filter_map(|d| d.get("existing").filter(|v| v.is_u64()).cloned()));
+                    if let Some(first) = ids.first().cloned() {
+                        h.session.execute("library.select", &json!({"ids": ids, "active": first})).map_err(|e| e.to_string())?;
+                    }
+                }
+                Box::new(h)
+            }
+        };
    let mut out = std::io::stdout().lock();
    let mut failed = 0;
    for s in &steps {
@@ -474,6 +606,12 @@ fn take_value<'a>(args: &'a [String], i: &mut usize, flag: &str) -> Result<&'a s
    args.get(*i).map(String::as_str).ok_or_else(|| format!("{flag} needs a value"))
 }

+/// The port an `--connect` address names, for the recovery hint. The whole address when it has
+/// no port, so a hint is never built from a guess.
+fn connect_port(addr: &str) -> &str {
+    addr.rsplit_once(':').map_or(addr, |(_, port)| port)
+}
+
 fn render(args: &[String]) -> Result<(), String> {
    let mut input = None;
    let mut output = None;
@@ -537,7 +675,7 @@ fn render(args: &[String]) -> Result<(), String> {
    for (k, v) in opts {
        p[k] = v;
    }
-    let mut o = ExportOptions::from_json(&p);
+    let mut o = ExportOptions::from_params(&p).map_err(|e| e.to_string())?;
    if p.get("format").is_none() {
        let ext = Path::new(&output).extension().map(|e| e.to_string_lossy().to_string()).unwrap_or_default();
        o.format = ExportFormat::parse(&ext)
@@ -633,6 +771,9 @@ fn snapshot(args: &[String]) -> Result<(), String> {
        Some(p.with_file_name(format!("{stem}-{shots}.{ext}")).to_string_lossy().to_string())
    };
    let mut wrote_output = false;
+    // Issue #166: a scripted request that fails still gets its reply printed and the run carries
+    // on (like `run --keep-going`), but the exit status reports it — CI judges by exit status.
+    let mut failed = 0usize;
    if let Some(script) = &script {
        let text = std::fs::read_to_string(script).map_err(|e| format!("{script}: {e}"))?;
        let mut out = std::io::stdout().lock();
@@ -665,6 +806,9 @@ fn snapshot(args: &[String]) -> Result<(), String> {
                }
                _ => h.request(&method, params, timeout),
            };
+            if reply["ok"] != true {
+                failed += 1;
+            }
            if let Some(o) = reply.as_object_mut() {
                o.insert("id".into(), id);
                // wall time of the request (incl. the frames it ran), and since the start
@@ -701,7 +845,7 @@ fn snapshot(args: &[String]) -> Result<(), String> {
        }
    }
    eprintln!("lightcraft-cli snapshot: done in {:.2} s ({} frames)", t0.elapsed().as_secs_f64(), h.frames());
-    Ok(())
+    if failed > 0 { Err(format!("{failed} scripted request(s) failed")) } else { Ok(()) }
 }

 fn commands(args: &[String]) -> Result<(), String> {
@@ -19,6 +19,19 @@ fn gradient_png(path: &std::path::Path) {
    std::fs::write(path, png).unwrap();
 }

+#[test]
+fn calibrate_reads_raf_inputs_and_reports_bad_files() {
+    let input = tmp("invalid.RAF");
+    std::fs::write(&input, b"FUJIFILMCCD-RAW").unwrap();
+    let out = tmp("raf-profiles");
+    let result = Command::new(BIN).args(["calibrate", "--out"]).arg(&out).arg(&input).output().unwrap();
+    assert!(!result.status.success());
+    let stderr = String::from_utf8_lossy(&result.stderr);
+    assert!(stderr.contains("1 of 1 raw files"), "RAF was silently ignored: {stderr}");
+    assert!(stderr.contains("invalid.RAF") && stderr.contains("no profile written"), "{stderr}");
+    assert!(!out.join("X-T4.json").exists(), "bad input must not produce a profile");
+}
+
 fn mean(path: &std::path::Path) -> f64 {
    let d = lightcraft_codecs::decode(&std::fs::read(path).unwrap(), Default::default()).unwrap();
    let img = d.to_srgb8();
@@ -154,10 +167,14 @@ fn snapshot_subcommand_renders_the_ui_headlessly() {
    std::fs::write(
        &script,
        format!(
-            "# comment\n{}\n{}\n{}\n{}\n",
+            "# comment\n{}\n{}\n{}\n{}\n{}\n{}\n",
            json!({"method": "ui.set", "params": {"view": "photoGrid"}}),
+            // (settled: under load a grid shot taken before its thumbnails is darker than the
+            // dimmed export dialog over them, and the comparison below fails)
+            json!({"method": "ui.settle", "params": {"timeoutMs": 20000}}),
            json!({"method": "ui.screenshot"}),
            json!({"method": "engine.execute", "params": {"command": "dialog.export"}}),
+            json!({"method": "ui.settle", "params": {"timeoutMs": 20000}}),
            json!({"method": "ui.screenshot", "params": {"path": b.to_str().unwrap()}}),
        ),
    )
@@ -168,7 +185,7 @@ fn snapshot_subcommand_renders_the_ui_headlessly() {
        .unwrap();
    assert!(o.status.success(), "{}", String::from_utf8_lossy(&o.stderr));
    let replies: Vec<Value> = String::from_utf8_lossy(&o.stdout).lines().map(|l| serde_json::from_str(l).unwrap()).collect();
-    assert_eq!(replies.len(), 4);
+    assert_eq!(replies.len(), 6);
    assert!(replies.iter().all(|r| r["ok"] == true), "{replies:?}");
    for (p, dimmed) in [(&a, false), (&b, true)] {
        let d = lightcraft_codecs::decode(&std::fs::read(p).unwrap(), Default::default()).unwrap();
@@ -183,6 +200,75 @@ fn snapshot_subcommand_renders_the_ui_headlessly() {
    assert_eq!((d.width, d.height), (640, 480));
 }

+/// Issue #166: a scripted request that fails makes `snapshot` exit non-zero. The failed reply is
+/// still printed, the later lines still run, and the final `-o` screenshot is still written.
+#[test]
+fn snapshot_script_failure_exits_non_zero() {
+    let script = tmp("snap-fail.jsonl");
+    let out = tmp("snap-fail.png");
+    std::fs::write(
+        &script,
+        format!(
+            "{}\n{}\n",
+            json!({"method": "ui.set", "params": {"view": "grid"}}), // not a view: `photoGrid`, `detail`, …
+            json!({"method": "ui.set", "params": {"view": "photoGrid"}}),
+        ),
+    )
+    .unwrap();
+    let _ = std::fs::remove_file(&out);
+    let o = Command::new(BIN)
+        .args(["snapshot", "--demo", "--script", script.to_str().unwrap(), "-o", out.to_str().unwrap(), "--size", "320x200"])
+        .output()
+        .unwrap();
+    let stderr = String::from_utf8_lossy(&o.stderr);
+    assert!(!o.status.success(), "a failed scripted request must fail the run\n{stderr}");
+    assert!(stderr.contains("1 scripted request(s) failed"), "{stderr}");
+    let replies: Vec<Value> = String::from_utf8_lossy(&o.stdout).lines().map(|l| serde_json::from_str(l).unwrap()).collect();
+    assert_eq!(replies.len(), 2, "{replies:?}");
+    assert_eq!(replies[0]["ok"], false, "{replies:?}");
+    assert!(replies[0]["error"].as_str().unwrap_or("").contains("grid"), "{replies:?}");
+    assert_eq!(replies[1]["ok"], true, "{replies:?}");
+    // continue-and-report: the final screenshot is still written
+    let d = lightcraft_codecs::decode(&std::fs::read(&out).unwrap(), Default::default()).unwrap();
+    assert_eq!((d.width, d.height), (320, 200));
+}
+
+/// Issue #136: with the GPU switched off from the environment the UI starts and renders on the CPU,
+/// without creating a GPU device (no driver is loaded), and says why.
+#[test]
+fn snapshot_starts_without_a_gpu() {
+    let script = tmp("nogpu.jsonl");
+    std::fs::write(
+        &script,
+        format!(
+            "{}\n{}\n{}\n",
+            json!({"method": "ui.set", "params": {"view": "photoGrid"}}),
+            json!({"method": "engine.execute", "params": {"command": "app.gpu"}}),
+            json!({"method": "ui.screenshot"}),
+        ),
+    )
+    .unwrap();
+    for (var, value, reason) in [("LIGHTCRAFT_GPU", "0", "LIGHTCRAFT_GPU=0"), ("LIGHTCRAFT_GPU_BACKEND", "off", "LIGHTCRAFT_GPU_BACKEND=off")] {
+        let out = tmp(&format!("nogpu-{var}.png"));
+        let o = Command::new(BIN)
+            .env_remove("LIGHTCRAFT_GPU")
+            .env_remove("LIGHTCRAFT_GPU_BACKEND")
+            .env(var, value)
+            .args(["snapshot", "--demo", "--script", script.to_str().unwrap(), "-o", out.to_str().unwrap(), "--size", "480x320"])
+            .output()
+            .unwrap();
+        assert!(o.status.success(), "{var}: {}", String::from_utf8_lossy(&o.stderr));
+        let replies: Vec<Value> = String::from_utf8_lossy(&o.stdout).lines().map(|l| serde_json::from_str(l).unwrap()).collect();
+        assert!(replies.iter().all(|r| r["ok"] == true), "{replies:?}");
+        let gpu = &replies[1]["result"];
+        assert_eq!(gpu["available"], false, "{var}: {gpu}");
+        assert_eq!(gpu["adapter"], Value::Null, "{var}: no device was created: {gpu}");
+        assert!(gpu["reason"].as_str().is_some_and(|r| r.contains(reason)), "{var}: {gpu}");
+        let d = lightcraft_codecs::decode(&std::fs::read(&out).unwrap(), Default::default()).unwrap();
+        assert_eq!((d.width, d.height), (480, 320));
+    }
+}
+
 fn run_cli(args: &[&str], stdin: Option<&str>) -> (bool, Vec<Value>, String) {
    let mut child = Command::new(BIN).arg("run").args(args).stdin(Stdio::piped()).stdout(Stdio::piped()).stderr(Stdio::piped()).spawn().unwrap();
    if let Some(text) = stdin {
@@ -256,7 +342,9 @@ fn devices_are_listed_and_imported_from() {
    assert_eq!(dev["name"], "CARD", "{line}");
    // the import review of its DCIM folder finds the photo
    let dcim = dev["path"].as_str().unwrap().to_string();
-    let o = Command::new(BIN).args(["run", "library.importPreview", &format!("paths=[\"{dcim}\"]")]).output().unwrap();
+    // JSON-escaped: a Windows path has backslashes
+    let paths = serde_json::to_string(&[&dcim]).unwrap();
+    let o = Command::new(BIN).args(["run", "library.importPreview", &format!("paths={paths}")]).output().unwrap();
    let line: Value = serde_json::from_slice(o.stdout.split(|b| *b == b'\n').next().unwrap()).unwrap();
    assert_eq!(line["result"]["candidates"].as_array().map(Vec::len), Some(1), "{line}");
 }
@@ -288,3 +376,39 @@ fn a_library_open_in_another_process_is_refused() {
    assert_eq!(lines[0]["ok"], true);
    let _ = std::fs::remove_dir_all(&lib);
 }
+
+/// Issue #167: when `--connect ADDR` cannot reach the app, the recovery hint must name the port
+/// ADDR actually names — following the old fixed "7980" left the retry connecting elsewhere.
+#[test]
+fn connect_failure_hint_names_the_attempted_port() {
+    let (ok, _lines, err) = run_cli(&["--connect", "127.0.0.1:18437", "ui.inspect"], None);
+    assert!(!ok);
+    assert!(err.contains("--control 18437"), "the hint must name the port it tried: {err}");
+    assert!(!err.contains("--control 7980"), "{err}");
+}
+
+/// The CLI logs warnings on stderr (#168): with `RUST_LOG=warn` an unknown GPU backend name is
+/// reported, and `RUST_LOG=off` silences it. Before, no logger was installed and nothing appeared.
+#[test]
+fn warnings_are_logged_on_stderr() {
+    let input = tmp("log-in.png");
+    gradient_png(&input);
+    let out = tmp("log-out.jpg");
+    let run = |level: &str| {
+        let o = Command::new(BIN)
+            .args(["render", input.to_str().unwrap(), "-o", out.to_str().unwrap()])
+            .env("LIGHTCRAFT_GPU_BACKEND", "bogus")
+            .env("RUST_LOG", level)
+            .env_remove("LIGHTCRAFT_LOG")
+            .env_remove("LIGHTCRAFT_GPU")
+            .output()
+            .unwrap();
+        let stderr = String::from_utf8_lossy(&o.stderr).into_owned();
+        assert!(o.status.success(), "{stderr}");
+        stderr
+    };
+    let warn = run("warn");
+    assert!(warn.contains("LIGHTCRAFT_GPU_BACKEND=bogus names no known backend"), "{warn}");
+    let off = run("off");
+    assert!(!off.contains("names no known backend"), "{off}");
+}
@@ -21,6 +21,7 @@ lightcraft-preview = { workspace = true }
 serde = { workspace = true }
 serde_json = { workspace = true }
 log = { workspace = true }
+crc32fast = { workspace = true }

 [target.'cfg(target_arch = "wasm32")'.dependencies]
 eframe = { workspace = true, features = ["default_fonts", "glow"] }
@@ -232,6 +232,18 @@ impl Backend {
        }
    }

+    /// Is there a file at `path`?
+    pub async fn exists(&self, path: &str) -> Result<bool, String> {
+        match self {
+            Backend::Opfs(root) => Ok(Self::opfs_file(root, path, false).await?.is_some()),
+            Backend::Idb(db) => {
+                let (_tx, store) = Self::idb_store(db, false)?;
+                let n = idb_req(&store.count_with_key(&path.into()).map_err(err)?).await?;
+                Ok(n.as_f64().is_some_and(|n| n > 0.0))
+            }
+        }
+    }
+
    pub async fn remove(&self, path: &str) -> Result<(), String> {
        match self {
            Backend::Opfs(root) => {
@@ -309,14 +321,25 @@ async fn dir_keys(dir: &FileSystemDirectoryHandle) -> Result<Vec<String>, String
    Ok(out)
 }

-/// Ask the browser not to evict our storage under pressure (best effort; fire and forget).
-pub fn request_persistence() {
-    if let Some(sm) = storage_manager()
-        && let Ok(p) = sm.persist()
-    {
-        wasm_bindgen_futures::spawn_local(async move {
-            let granted = JsFuture::from(p).await.ok().is_some_and(|v| v.is_truthy());
-            log::info!("lightcraft: persistent storage {}", if granted { "granted" } else { "not granted (best effort)" });
-        });
-    }
+/// Ask the browser not to evict our storage under pressure; `on_result(granted)` once known
+/// (`false` also when the browser has no storage manager).
+pub fn request_persistence(on_result: impl FnOnce(bool) + 'static) {
+    let Some(sm) = storage_manager() else {
+        on_result(false);
+        return;
+    };
+    wasm_bindgen_futures::spawn_local(async move {
+        // already persistent: nothing to ask
+        let already = match sm.persisted() {
+            Ok(p) => JsFuture::from(p).await.ok().is_some_and(|v| v.is_truthy()),
+            Err(_) => false,
+        };
+        let granted = already
+            || match sm.persist() {
+                Ok(p) => JsFuture::from(p).await.ok().is_some_and(|v| v.is_truthy()),
+                Err(_) => false,
+            };
+        log::info!("lightcraft: persistent storage {}", if granted { "granted" } else { "not granted" });
+        on_result(granted);
+    });
 }
@@ -0,0 +1,306 @@
+//! Library backups for the browser build: a plain zip (entries stored, not compressed — photos
+//! don't shrink) of the library files and every stored original, built one entry at a time so
+//! only one file is in wasm memory at once, and read back the same way for a restore.
+//!
+//! Layout of a backup:
+//! - `library/catalog.snap`, `library/catalog.log`, `library/presets.json`, … (see
+//!   [`crate::files::LIBRARY_FILES`]);
+//! - `originals/<content hash>/<file name>`: each imported photo's original bytes, under its own
+//!   name so an unzipped backup is browsable;
+//! - `README.txt`.
+//!
+//! Restoring never deletes anything: the library files go to a new library folder in browser
+//! storage, originals that aren't stored yet are added (they're named by content, so existing
+//! ones are identical), and only then does a small pointer file ([`ACTIVE_LIBRARY`]) switch to
+//! the restored library. The library that was there before stays in storage.
+//!
+//! No zip64: a backup holds at most [`MAX_BYTES`] and 65 535 entries.
+
+/// Storage key of the file naming the library folder in use (absent: `library`).
+pub const ACTIVE_LIBRARY: &str = "active-library";
+
+/// The default library folder.
+pub const DEFAULT_LIBRARY_DIR: &str = "library";
+
+/// Largest backup (offsets are 32-bit without zip64).
+pub const MAX_BYTES: u64 = 0xFFFF_FFFF - (64 << 20);
+
+const LOCAL_SIG: u32 = 0x0403_4b50;
+const CENTRAL_SIG: u32 = 0x0201_4b50;
+const END_SIG: u32 = 0x0605_4b50;
+/// General-purpose flag bit 11: names are UTF-8.
+const UTF8: u16 = 0x0800;
+/// 1980-01-01 00:00 in MS-DOS format (date, time).
+const DOS_DATE: u16 = (1 << 5) | 1;
+
+/// The readme inside every backup.
+pub const README: &str = "LightCraft library backup (browser version)\n\n\
+library/      the catalog (catalog.snap + catalog.log), presets, view state and preferences\n\
+originals/    every imported photo, as originals/<content hash>/<file name>\n\n\
+Restore it in LightCraft for the web with File > Restore Library from Backup...\n\
+The photos in originals/ are the untouched files you imported; edits live in the catalog.\n";
+
+/// Is `name` a safe library folder name (`library` or `library-<letters, digits, ->`)?
+pub fn valid_library_dir(name: &str) -> bool {
+    name == DEFAULT_LIBRARY_DIR
+        || name.strip_prefix("library-").is_some_and(|s| !s.is_empty() && s.len() <= 64 && s.chars().all(|c| c.is_ascii_alphanumeric() || c == '-'))
+}
+
+/// Is `h` a plausible content hash (used as a storage key segment)?
+pub fn valid_hash(h: &str) -> bool {
+    !h.is_empty() && h.len() <= 128 && h.chars().all(|c| c.is_ascii_alphanumeric())
+}
+
+/// Zip entry name for an original.
+pub fn original_entry(hash: &str, file_name: &str) -> String {
+    let name: String = file_name.chars().map(|c| if c == '/' || c == '\\' || c.is_control() { '_' } else { c }).collect();
+    let name = if name.is_empty() || name == "." || name == ".." { "original".to_string() } else { name };
+    format!("originals/{hash}/{name}")
+}
+
+/// Where a backup entry goes when restoring into library folder `dir`: `Some(storage key)`, or
+/// `None` to skip it (README, thumbnails, anything unknown or unsafe).
+pub fn restore_key(entry: &str, dir: &str) -> Option<String> {
+    if let Some(name) = entry.strip_prefix("library/") {
+        return crate::files::LIBRARY_FILES.contains(&name).then(|| format!("{dir}/{name}"));
+    }
+    let rest = entry.strip_prefix("originals/")?;
+    let (hash, _) = rest.split_once('/').unwrap_or((rest, ""));
+    valid_hash(hash).then(|| format!("originals/{hash}"))
+}
+
+fn u16le(v: &mut Vec<u8>, x: u16) {
+    v.extend_from_slice(&x.to_le_bytes());
+}
+fn u32le(v: &mut Vec<u8>, x: u32) {
+    v.extend_from_slice(&x.to_le_bytes());
+}
+
+struct Central {
+    name: String,
+    crc: u32,
+    size: u32,
+    offset: u32,
+}
+
+/// Writes a stored (uncompressed) zip piece by piece: [`ZipWriter::entry`] returns the local
+/// header to emit before the entry's bytes, [`ZipWriter::finish`] the central directory.
+#[derive(Default)]
+pub struct ZipWriter {
+    entries: Vec<Central>,
+    offset: u64,
+}
+
+impl ZipWriter {
+    /// The local header for `name` holding `data` (emit it, then `data`).
+    pub fn entry(&mut self, name: &str, data: &[u8]) -> Result<Vec<u8>, String> {
+        let size = u32::try_from(data.len()).map_err(|_| format!("{name}: larger than 4 GB"))?;
+        let name_len = u16::try_from(name.len()).map_err(|_| format!("{name}: name too long"))?;
+        if self.entries.len() >= usize::from(u16::MAX) {
+            return Err("too many files for one backup".into());
+        }
+        let header_len = 30 + u64::from(name_len);
+        if self.offset + header_len + u64::from(size) > MAX_BYTES {
+            return Err("the library is too large for one backup file (4 GB)".into());
+        }
+        let offset = u32::try_from(self.offset).map_err(|_| "backup too large".to_string())?;
+        let crc = crc32fast::hash(data);
+        let mut h = Vec::with_capacity(header_len as usize);
+        u32le(&mut h, LOCAL_SIG);
+        u16le(&mut h, 20); // version needed
+        u16le(&mut h, UTF8);
+        u16le(&mut h, 0); // stored
+        u16le(&mut h, 0); // time
+        u16le(&mut h, DOS_DATE);
+        u32le(&mut h, crc);
+        u32le(&mut h, size);
+        u32le(&mut h, size);
+        u16le(&mut h, name_len);
+        u16le(&mut h, 0); // extra
+        h.extend_from_slice(name.as_bytes());
+        self.offset += header_len + u64::from(size);
+        self.entries.push(Central { name: name.to_string(), crc, size, offset });
+        Ok(h)
+    }
+
+    /// The central directory and end record (emit last).
+    pub fn finish(self) -> Result<Vec<u8>, String> {
+        let mut cd = Vec::new();
+        for e in &self.entries {
+            u32le(&mut cd, CENTRAL_SIG);
+            u16le(&mut cd, 20); // made by
+            u16le(&mut cd, 20); // needed
+            u16le(&mut cd, UTF8);
+            u16le(&mut cd, 0);
+            u16le(&mut cd, 0);
+            u16le(&mut cd, DOS_DATE);
+            u32le(&mut cd, e.crc);
+            u32le(&mut cd, e.size);
+            u32le(&mut cd, e.size);
+            u16le(&mut cd, e.name.len() as u16);
+            u16le(&mut cd, 0); // extra
+            u16le(&mut cd, 0); // comment
+            u16le(&mut cd, 0); // disk
+            u16le(&mut cd, 0); // internal attrs
+            u32le(&mut cd, 0); // external attrs
+            u32le(&mut cd, e.offset);
+            cd.extend_from_slice(e.name.as_bytes());
+        }
+        let cd_offset = u32::try_from(self.offset).map_err(|_| "backup too large".to_string())?;
+        let cd_size = u32::try_from(cd.len()).map_err(|_| "backup too large".to_string())?;
+        let n = self.entries.len() as u16;
+        let mut out = cd;
+        u32le(&mut out, END_SIG);
+        u16le(&mut out, 0);
+        u16le(&mut out, 0);
+        u16le(&mut out, n);
+        u16le(&mut out, n);
+        u32le(&mut out, cd_size);
+        u32le(&mut out, cd_offset);
+        u16le(&mut out, 0); // comment
+        Ok(out)
+    }
+}
+
+/// One entry of a zip's central directory.
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct ZipEntry {
+    pub name: String,
+    pub crc: u32,
+    pub size: u64,
+    /// Offset of the entry's local header.
+    pub header: u64,
+    /// 0 = stored (the only method a restore reads).
+    pub method: u16,
+}
+
+fn rd16(b: &[u8], at: usize) -> Option<u16> {
+    Some(u16::from_le_bytes(b.get(at..at + 2)?.try_into().ok()?))
+}
+fn rd32(b: &[u8], at: usize) -> Option<u32> {
+    Some(u32::from_le_bytes(b.get(at..at + 4)?.try_into().ok()?))
+}
+
+/// How many bytes from the end of a zip to read to find its end record.
+pub fn tail_len(file_len: u64) -> u64 {
+    file_len.min(22 + 65_535)
+}
+
+/// The central directory's (offset, size) from the last [`tail_len`] bytes of a zip.
+pub fn find_central(tail: &[u8]) -> Result<(u64, u64), String> {
+    let at = (0..tail.len().saturating_sub(21)).rev().find(|&i| rd32(tail, i) == Some(END_SIG)).ok_or("not a zip file (no end record)")?;
+    let size = rd32(tail, at + 12).ok_or("truncated zip")?;
+    let offset = rd32(tail, at + 16).ok_or("truncated zip")?;
+    if size == u32::MAX || offset == u32::MAX {
+        return Err("zip64 backups are not supported".into());
+    }
+    Ok((u64::from(offset), u64::from(size)))
+}
+
+/// Parse a central directory.
+pub fn parse_central(cd: &[u8]) -> Result<Vec<ZipEntry>, String> {
+    let mut out = Vec::new();
+    let mut i = 0;
+    while i + 46 <= cd.len() {
+        if rd32(cd, i) != Some(CENTRAL_SIG) {
+            return Err("damaged zip directory".into());
+        }
+        let bad = || "damaged zip directory".to_string();
+        let method = rd16(cd, i + 10).ok_or_else(bad)?;
+        let crc = rd32(cd, i + 16).ok_or_else(bad)?;
+        let size = rd32(cd, i + 24).ok_or_else(bad)?;
+        let n = usize::from(rd16(cd, i + 28).ok_or_else(bad)?);
+        let extra = usize::from(rd16(cd, i + 30).ok_or_else(bad)?);
+        let comment = usize::from(rd16(cd, i + 32).ok_or_else(bad)?);
+        let header = rd32(cd, i + 42).ok_or_else(bad)?;
+        let name = cd.get(i + 46..i + 46 + n).ok_or_else(bad)?;
+        out.push(ZipEntry { name: String::from_utf8_lossy(name).into_owned(), crc, size: u64::from(size), header: u64::from(header), method });
+        i += 46 + n + extra + comment;
+    }
+    Ok(out)
+}
+
+/// Offset of an entry's data from its local header's first 30 bytes.
+pub fn data_offset(entry: &ZipEntry, local: &[u8]) -> Result<u64, String> {
+    if rd32(local, 0) != Some(LOCAL_SIG) {
+        return Err(format!("{}: damaged entry", entry.name));
+    }
+    let n = rd16(local, 26).ok_or("truncated entry")?;
+    let extra = rd16(local, 28).ok_or("truncated entry")?;
+    Ok(entry.header + 30 + u64::from(n) + u64::from(extra))
+}
+
+/// Check an entry's bytes.
+pub fn verify(entry: &ZipEntry, data: &[u8]) -> Result<(), String> {
+    if entry.method != 0 {
+        return Err(format!("{}: compressed entries are not supported (not a LightCraft backup?)", entry.name));
+    }
+    if data.len() as u64 != entry.size || crc32fast::hash(data) != entry.crc {
+        return Err(format!("{}: damaged (checksum mismatch)", entry.name));
+    }
+    Ok(())
+}
+
+/// A name for the restored library's folder.
+pub fn restored_dir_name(now_ms: f64) -> String {
+    format!("library-restored-{}", now_ms.max(0.0) as u64)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn build(files: &[(&str, &[u8])]) -> Vec<u8> {
+        let mut w = ZipWriter::default();
+        let mut out = Vec::new();
+        for (n, d) in files {
+            out.extend(w.entry(n, d).unwrap());
+            out.extend_from_slice(d);
+        }
+        out.extend(w.finish().unwrap());
+        out
+    }
+
+    #[test]
+    fn written_backups_read_back() {
+        let files: [(&str, &[u8]); 3] =
+            [("README.txt", README.as_bytes()), ("library/catalog.log", b"{\"seq\":1}\n"), ("originals/abc123/IMG 1.jpg", &[0, 1, 2, 3, 255])];
+        let zip = build(&files);
+        let tail = &zip[zip.len() - tail_len(zip.len() as u64) as usize..];
+        let (off, size) = find_central(tail).unwrap();
+        let entries = parse_central(&zip[off as usize..(off + size) as usize]).unwrap();
+        assert_eq!(entries.len(), 3);
+        for (e, (name, data)) in entries.iter().zip(files) {
+            assert_eq!(e.name, name);
+            let start = data_offset(e, &zip[e.header as usize..e.header as usize + 30]).unwrap() as usize;
+            let got = &zip[start..start + e.size as usize];
+            assert_eq!(got, data);
+            verify(e, got).unwrap();
+        }
+        // damage is caught
+        let e = &entries[2];
+        assert!(verify(e, &[0, 1, 2, 3, 254]).is_err());
+        assert!(find_central(b"not a zip at all, just some text").is_err());
+    }
+
+    #[test]
+    fn restore_keys_are_safe() {
+        assert_eq!(restore_key("library/catalog.snap", "library-restored-1").as_deref(), Some("library-restored-1/catalog.snap"));
+        assert_eq!(restore_key("library/../../x", "library-r"), None);
+        assert_eq!(restore_key("library/evil.bin", "library-r"), None);
+        assert_eq!(restore_key("originals/abc123/IMG.jpg", "d").as_deref(), Some("originals/abc123"));
+        assert_eq!(restore_key("originals/../library/catalog.log", "d"), None);
+        assert_eq!(restore_key("README.txt", "d"), None);
+        assert_eq!(restore_key("thumbs/x.jpg", "d"), None);
+        assert_eq!(original_entry("abc", "a/b\\c.jpg"), "originals/abc/a_b_c.jpg");
+        assert_eq!(original_entry("abc", ".."), "originals/abc/original");
+        assert!(valid_library_dir("library") && valid_library_dir("library-restored-17"));
+        assert!(!valid_library_dir("library-../x") && !valid_library_dir("originals") && !valid_library_dir("library-"));
+    }
+
+    #[test]
+    fn size_limits_are_errors_not_panics() {
+        let mut w = ZipWriter { offset: MAX_BYTES - 10, ..Default::default() };
+        assert!(w.entry("x", &[0; 64]).is_err());
+    }
+}
@@ -49,6 +49,8 @@ struct Mirror {
    files: BTreeMap<String, Vec<u8>>,
    /// Dirty files, least recently modified first.
    dirty: Vec<(String, Dirty)>,
+    /// Why the last flush to browser storage failed (quota, eviction…), until one succeeds.
+    error: Option<String>,
 }

 impl Mirror {
@@ -138,6 +140,18 @@ impl Files {
        }
    }

+    /// Record the outcome of a flush to browser storage: `Some(why)` when it failed, `None` once
+    /// one succeeds. While a flush is failing, the catalog [`Store`] refuses new writes, so the
+    /// engine keeps the changes queued and reports them unsaved (`library.info` → `unsavedOps`,
+    /// the top bar's warning) instead of pretending they were saved.
+    pub fn set_error(&self, e: Option<String>) {
+        self.lock().error = e;
+    }
+
+    pub fn error(&self) -> Option<String> {
+        self.lock().error.clone()
+    }
+
    /// A catalog [`Store`] over these files.
    pub fn store(&self) -> FilesStore {
        FilesStore(self.clone())
@@ -147,19 +161,32 @@ impl Files {
 /// [`Store`] implementation over [`Files`].
 pub struct FilesStore(Files);

+impl FilesStore {
+    /// Writes fail while browser storage does (see [`Files::set_error`]).
+    fn writable(&self) -> io::Result<()> {
+        match self.0.error() {
+            Some(e) => Err(io::Error::other(format!("browser storage: {e}"))),
+            None => Ok(()),
+        }
+    }
+}
+
 impl Store for FilesStore {
    fn read(&mut self, name: &str) -> io::Result<Option<Vec<u8>>> {
        Ok(self.0.get(name))
    }
    fn write_atomic(&mut self, name: &str, data: &[u8]) -> io::Result<()> {
+        self.writable()?;
        self.0.write(name, data);
        Ok(())
    }
    fn append(&mut self, name: &str, data: &[u8]) -> io::Result<()> {
+        self.writable()?;
        self.0.append(name, data);
        Ok(())
    }
    fn truncate(&mut self, name: &str, len: u64) -> io::Result<()> {
+        self.writable()?;
        self.0.truncate(name, len as usize);
        Ok(())
    }
@@ -224,6 +251,37 @@ mod tests {
        assert_eq!(names, ["catalog.snap", "catalog.log"]);
    }

+    /// A failing flush (quota exceeded, storage evicted) is not silent: commands report the change
+    /// as unsaved and the engine keeps it queued; once storage works again it is written.
+    #[test]
+    fn flush_failures_show_as_unsaved_and_are_retried() {
+        let mut disk = BTreeMap::new();
+        let files = Files::default();
+        let mut s = Session::new();
+        let stores = LibraryStores { dir: "browser".into(), catalog: Box::new(files.store()), files: Box::new(files.store()), on_disk: false };
+        s.open_library_in(stores, true).unwrap();
+        flush(&files, &mut disk);
+        files.set_error(Some("QuotaExceededError".into()));
+        let r = s.execute("photo.rate", &json!({"rating": 5}));
+        assert!(matches!(r, Err(lightcraft_engine::EngineError::NotSaved(_))), "{r:?}");
+        let (ops, why) = s.unsaved().unwrap();
+        assert!(ops > 0 && why.contains("QuotaExceeded"), "{why}");
+        files.set_error(None);
+        s.persist_if_dirty();
+        s.persist().unwrap();
+        assert!(s.unsaved().is_none(), "written once storage works again");
+        flush(&files, &mut disk);
+        let id = s.selection.active.unwrap();
+        let files2 = Files::default();
+        for (k, v) in &disk {
+            files2.preload(k, v.clone());
+        }
+        let mut s2 = Session::new();
+        let stores = LibraryStores { dir: "browser".into(), catalog: Box::new(files2.store()), files: Box::new(files2.store()), on_disk: false };
+        s2.open_library_in(stores, true).unwrap();
+        assert_eq!(s2.catalog.photo(id).unwrap().rating, 5, "the rating survived");
+    }
+
    #[test]
    fn library_survives_reload_through_flushes() {
        let mut disk = BTreeMap::new();
@@ -16,6 +16,7 @@
 #![forbid(unsafe_code)]
 #![deny(clippy::unwrap_used, clippy::expect_used, clippy::panic, clippy::unimplemented, clippy::todo, clippy::unreachable)]

+pub mod backup;
 pub mod bench;
 pub mod files;
 pub mod store;
@@ -24,6 +25,8 @@ pub mod wire;
 #[cfg(target_arch = "wasm32")]
 mod backend;
 #[cfg(target_arch = "wasm32")]
+mod safety;
+#[cfg(target_arch = "wasm32")]
 mod web;
 #[cfg(target_arch = "wasm32")]
 mod workers;
@@ -0,0 +1,256 @@
+//! Keeping a library in the browser safe: notices the user must see (a failed save, storage the
+//! browser may evict, a file that couldn't be stored), one tab at a time per library, a message
+//! instead of a dead page after a panic, and backup / restore of the whole library
+//! ([`crate::backup`]).
+
+use std::cell::RefCell;
+use std::collections::HashMap;
+
+use js_sys::{Reflect, Uint8Array};
+use wasm_bindgen::JsCast;
+use wasm_bindgen::prelude::*;
+use wasm_bindgen_futures::JsFuture;
+
+use crate::backend::Backend;
+use crate::backup::{
+    ACTIVE_LIBRARY, README, ZipWriter, data_offset, find_central, original_entry, parse_central, restore_key, restored_dir_name, tail_len,
+    valid_hash, verify,
+};
+use crate::files::{Files, LIBRARY_FILES};
+use crate::store::storage_key;
+
+thread_local! {
+    /// Messages for the user, shown by the app on its next frame.
+    static NOTICES: RefCell<Vec<String>> = const { RefCell::new(Vec::new()) };
+}
+
+/// Queue a message for the user (shown for several seconds; also logged).
+pub fn notice(text: impl Into<String>) {
+    let text = text.into();
+    log::warn!("{text}");
+    NOTICES.with(|n| n.borrow_mut().push(text));
+    crate::web::request_repaint();
+}
+
+/// Messages queued since the last call.
+pub fn take_notices() -> Vec<String> {
+    NOTICES.with(|n| std::mem::take(&mut *n.borrow_mut()))
+}
+
+fn document() -> Option<web_sys::Document> {
+    web_sys::window()?.document()
+}
+
+/// Ask the user (the browser's own confirm box). `false` when it can't be shown.
+pub fn confirm(text: &str) -> bool {
+    web_sys::window().and_then(|w| w.confirm_with_message(text).ok()).unwrap_or(false)
+}
+
+/// Cover the page with a message (the app can't continue, or must not start).
+pub fn show_blocking(text: &str) {
+    let Some(doc) = document() else { return };
+    let el = match doc.get_element_by_id("lightcraft_blocking") {
+        Some(el) => el,
+        None => {
+            let Ok(el) = doc.create_element("div") else { return };
+            el.set_id("lightcraft_blocking");
+            let _ = el.set_attribute(
+                "style",
+                "position:fixed;inset:0;z-index:10;display:flex;align-items:center;justify-content:center;padding:32px;\
+                 background:#1c1c1c;color:#e0e0e0;font:15px/1.5 system-ui,-apple-system,'Segoe UI',sans-serif;text-align:center;white-space:pre-line",
+            );
+            if let Some(body) = doc.body() {
+                let _ = body.append_child(&el);
+            }
+            el
+        }
+    };
+    el.set_text_content(Some(text));
+    if let Some(loading) = doc.get_element_by_id("lightcraft_loading") {
+        loading.remove();
+    }
+}
+
+/// `panic = "abort"` on wasm: a panic ends the module. Say so on the page instead of leaving a
+/// frozen canvas, and say that the stored library is intact.
+pub fn install_panic_hook() {
+    std::panic::set_hook(Box::new(|info| {
+        let msg = match (info.payload().downcast_ref::<&str>(), info.payload().downcast_ref::<String>()) {
+            (Some(s), _) => (*s).to_string(),
+            (_, Some(s)) => s.clone(),
+            _ => "unknown error".into(),
+        };
+        let at = info.location().map(|l| format!(" at {}:{}", l.file(), l.line())).unwrap_or_default();
+        log::error!("LightCraft panicked{at}: {msg}");
+        show_blocking(&format!(
+            "LightCraft stopped after an internal error:\n{msg}\n\nThe library saved in this browser is kept. Reload the page to continue.\n\
+             If it happens again right away, a photo may be the cause: reload with ?workers=0 or report the error."
+        ));
+    }));
+}
+
+/// The name of the lock that keeps a library to one tab.
+const TAB_LOCK: &str = "lightcraft-library";
+
+/// Hold the library lock for as long as this page lives (Web Locks API). `Some(true)`: ours;
+/// `Some(false)`: another tab of this site has it; `None`: the browser can't tell (no Web Locks).
+pub async fn acquire_tab_lock() -> Option<bool> {
+    let nav = Reflect::get(&js_sys::global(), &"navigator".into()).ok()?;
+    let locks = Reflect::get(&nav, &"locks".into()).ok().filter(|l| !l.is_undefined() && !l.is_null())?;
+    let request: js_sys::Function = Reflect::get(&locks, &"request".into()).ok()?.dyn_into().ok()?;
+    let opts = js_sys::Object::new();
+    Reflect::set(&opts, &"ifAvailable".into(), &true.into()).ok()?;
+    let granted = js_sys::Promise::new(&mut |resolve, _reject| {
+        let cb = Closure::once_into_js(move |lock: JsValue| -> JsValue {
+            let ours = !lock.is_null() && !lock.is_undefined();
+            let _ = resolve.call1(&JsValue::NULL, &ours.into());
+            // keep the lock until the page goes away: a promise that never settles
+            if ours { js_sys::Promise::new(&mut |_, _| {}).into() } else { JsValue::NULL }
+        });
+        if let Err(e) = request.call3(&locks, &TAB_LOCK.into(), &opts, &cb) {
+            log::warn!("Web Locks request failed: {e:?}");
+        }
+    });
+    JsFuture::from(granted).await.ok().map(|v| v.is_truthy())
+}
+
+/// Offer a blob as a download named `name`.
+pub fn download_blob(name: &str, blob: &web_sys::Blob) -> Result<(), String> {
+    let e = |e: JsValue| format!("download failed: {e:?}");
+    let url = web_sys::Url::create_object_url_with_blob(blob).map_err(e)?;
+    let doc = document().ok_or("no document")?;
+    let a: web_sys::HtmlAnchorElement = doc.create_element("a").map_err(e)?.unchecked_into();
+    a.set_href(&url);
+    a.set_download(name);
+    a.click();
+    // revoke once the download has started
+    let revoke = Closure::once_into_js(move || {
+        let _ = web_sys::Url::revoke_object_url(&url);
+    });
+    if let Some(w) = web_sys::window() {
+        let _ = w.set_timeout_with_callback_and_timeout_and_arguments_0(revoke.unchecked_ref(), 60_000);
+    }
+    Ok(())
+}
+
+/// File ▸ Back Up Library…: a zip of the library files (as the app has them, saved or not) and
+/// every original in storage, built entry by entry into the browser's memory (outside the wasm
+/// heap) and downloaded. `names`: content hash → the photo's file name.
+pub async fn backup(files: Files, backend: Backend, names: HashMap<String, String>) -> Result<(usize, f64), String> {
+    let parts = js_sys::Array::new();
+    let mut zip = ZipWriter::default();
+    let mut bytes = 0f64;
+    let mut add = |zip: &mut ZipWriter, name: &str, data: &[u8]| -> Result<(), String> {
+        let header = zip.entry(name, data)?;
+        parts.push(&Uint8Array::from(&header[..]));
+        parts.push(&Uint8Array::from(data));
+        bytes += (header.len() + data.len()) as f64;
+        Ok(())
+    };
+    add(&mut zip, "README.txt", README.as_bytes())?;
+    for name in LIBRARY_FILES {
+        if let Some(d) = files.get(name) {
+            add(&mut zip, &format!("library/{name}"), &d)?;
+        }
+    }
+    let mut originals = 0;
+    for hash in backend.list("originals").await? {
+        if !valid_hash(&hash) {
+            continue;
+        }
+        match backend.read(&storage_key(&hash)).await {
+            Ok(Some(data)) => {
+                let name = names.get(&hash).map_or("original", String::as_str);
+                add(&mut zip, &original_entry(&hash, name), &data)?;
+                originals += 1;
+            }
+            Ok(None) => {}
+            Err(e) => return Err(format!("reading an original from browser storage: {e}")),
+        }
+    }
+    let tail = zip.finish()?;
+    parts.push(&Uint8Array::from(&tail[..]));
+    let opts = web_sys::BlobPropertyBag::new();
+    opts.set_type("application/zip");
+    let blob = web_sys::Blob::new_with_u8_array_sequence_and_options(&parts, &opts).map_err(|e| format!("{e:?}"))?;
+    let day: String = String::from(js_sys::Date::new_0().to_iso_string()).chars().take(10).collect();
+    download_blob(&format!("lightcraft-library-backup-{day}.zip"), &blob)?;
+    Ok((originals, bytes + tail.len() as f64))
+}
+
+/// Bytes `start..end` of a picked file.
+async fn read_range(file: &web_sys::File, start: u64, end: u64) -> Result<Vec<u8>, String> {
+    let blob = file.slice_with_f64_and_f64(start as f64, end as f64).map_err(|e| format!("{e:?}"))?;
+    let buf = JsFuture::from(blob.array_buffer()).await.map_err(|e| format!("{e:?}"))?;
+    Ok(Uint8Array::new(&buf).to_vec())
+}
+
+/// Restore a backup into a new library folder (nothing in storage is deleted or overwritten),
+/// then point [`ACTIVE_LIBRARY`] at it. Returns the folder's name; the caller reloads the page.
+pub async fn restore(file: web_sys::File, backend: Backend) -> Result<String, String> {
+    let len = file.size() as u64;
+    let tail = read_range(&file, len - tail_len(len), len).await?;
+    let (cd_offset, cd_size) = find_central(&tail)?;
+    let cd = read_range(&file, cd_offset, cd_offset + cd_size).await?;
+    let entries = parse_central(&cd)?;
+    if !entries.iter().any(|e| e.name == "library/catalog.snap" || e.name == "library/catalog.log") {
+        return Err("this isn't a LightCraft library backup (no library/catalog files)".into());
+    }
+    let dir = restored_dir_name(js_sys::Date::now());
+    let mut written = 0usize;
+    for e in &entries {
+        let Some(key) = restore_key(&e.name, &dir) else { continue };
+        // originals are named by their content: one already stored is the same file
+        if key.starts_with("originals/") && backend.exists(&key).await? {
+            continue;
+        }
+        let local = read_range(&file, e.header, e.header + 30).await?;
+        let start = data_offset(e, &local)?;
+        let data = read_range(&file, start, start + e.size).await?;
+        verify(e, &data)?;
+        backend.write(&key, &data).await.map_err(|err| format!("storing {}: {err}", e.name))?;
+        written += 1;
+    }
+    backend.write(ACTIVE_LIBRARY, dir.as_bytes()).await?;
+    log::info!("lightcraft: restored {written} files into {dir}");
+    Ok(dir)
+}
+
+/// File ▸ Restore Library from Backup…: confirm, pick the zip, restore, reload.
+pub fn pick_and_restore(backend: Backend, before_reload: impl FnOnce() + 'static) {
+    let ok = confirm(
+        "Restore a LightCraft library backup?\n\nThe backup becomes the library in this browser and the page reloads. \
+         The current library is not deleted: it stays in browser storage.",
+    );
+    if !ok {
+        return;
+    }
+    let Some(doc) = document() else { return };
+    let Ok(input) = doc.create_element("input").map(|e| e.unchecked_into::<web_sys::HtmlInputElement>()) else { return };
+    input.set_type("file");
+    input.set_accept(".zip,application/zip");
+    let inp = input.clone();
+    let mut before_reload = Some(before_reload);
+    let on_change = Closure::<dyn FnMut()>::new(move || {
+        let Some(file) = inp.files().and_then(|f| f.get(0)) else { return };
+        let backend = backend.clone();
+        let before = before_reload.take();
+        notice(format!("Restoring {}…", file.name()));
+        wasm_bindgen_futures::spawn_local(async move {
+            match restore(file, backend).await {
+                Ok(_) => {
+                    if let Some(f) = before {
+                        f();
+                    }
+                    if let Some(w) = web_sys::window() {
+                        let _ = w.location().reload();
+                    }
+                }
+                Err(e) => notice(format!("Restore failed: {e}. Nothing was changed: the current library is still in use.")),
+            }
+        });
+    });
+    input.set_onchange(Some(on_change.as_ref().unchecked_ref()));
+    on_change.forget();
+    input.click();
+}
@@ -15,16 +15,21 @@ use wasm_bindgen::JsCast;
 use wasm_bindgen::prelude::*;

 use crate::backend::Backend;
+use crate::backup::{ACTIVE_LIBRARY, DEFAULT_LIBRARY_DIR, valid_library_dir};
 use crate::bench::Bench;
 use crate::files::{Files, FlushOp, LIBRARY_FILES};
+use crate::safety::{self, notice};
 use crate::store::{Originals, content_hash, download_name, storage_key};
 use crate::wire::ThumbIndex;
 use crate::workers::{THUMB_INDEX, Workers};

 const ACCEPT: &str = ".jpg,.jpeg,.png,.tif,.tiff,.webp,.dng,.cr2,.nef,.arw,.psd,.jxl,.gif,.bmp";

-/// Where the library files live in browser storage.
-const LIBRARY_DIR: &str = "library";
+/// After a failed save, wait this long before trying again (ms).
+const SAVE_RETRY_MS: f64 = 2000.0;
+
+/// How long a notice stays on screen (s).
+const NOTICE_SECS: f64 = 8.0;

 /// How often view state, UI prefs and the thumbnail index are saved (ms).
 const SAVE_EVERY_MS: f64 = 1000.0;
@@ -45,8 +50,18 @@ fn set_status(text: &str) {
    }
 }

-fn library_key(name: &str) -> String {
-    format!("{LIBRARY_DIR}/{name}")
+/// Storage key of library file `name` in library folder `dir`.
+fn library_key(dir: &str, name: &str) -> String {
+    format!("{dir}/{name}")
+}
+
+/// Repaint the app (notices from async tasks).
+pub(crate) fn request_repaint() {
+    CTX.with(|c| {
+        if let Some(c) = c.borrow().as_ref() {
+            c.request_repaint();
+        }
+    });
 }

 /// URL options (`?bench&store=idb&workers=2&reset`).
@@ -86,8 +101,9 @@ async fn store_file(originals: Originals, backend: Option<Backend>, name: String
    if let Some(b) = &backend
        && let Err(e) = b.write(&storage_key(&hash), &bytes).await
    {
-        // still importable for this session; it won't survive a reload
-        log::error!("storing {name} in browser storage failed: {e}");
+        // a photo whose bytes aren't stored would be gone after a reload: don't add it
+        notice(format!("{name} was not added: browser storage refused it ({e}). Free up space or back up and clear old photos."));
+        return;
    }
    originals.added(&name, &hash, Arc::from(bytes));
    ctx.request_repaint();
@@ -148,8 +164,42 @@ fn download(path: &str, bytes: &[u8]) -> Result<(), String> {
    Ok(())
 }

-fn services(originals: Originals, backend: Option<Backend>, ctx: egui::Context) -> Services {
+fn services(originals: Originals, backend: Option<Backend>, files: Files, frozen: Rc<Cell<bool>>, ctx: egui::Context) -> Services {
+    let (backup_backend, backup_files) = (backend.clone(), files);
+    let restore_backend = backend.clone();
    Services {
+        backup_library: Some(Box::new(move |session: &mut Session| {
+            let Some(b) = backup_backend.clone() else { return Err("nothing is stored in this browser session (?store=memory)".into()) };
+            // the photos' own names for the originals in the zip
+            let names: std::collections::HashMap<String, String> = session
+                .catalog
+                .photos()
+                .filter_map(|p| match &p.source {
+                    Source::File { path } => crate::store::hash_of_path(path).map(|h| (h.to_string(), p.file_name.clone())),
+                    _ => None,
+                })
+                .collect();
+            let files = backup_files.clone();
+            notice("Backing up the library… (the download starts when it's ready)");
+            wasm_bindgen_futures::spawn_local(async move {
+                match safety::backup(files, b, names).await {
+                    Ok((n, bytes)) => notice(format!(
+                        "Library backed up: {n} original{} ({:.1} MB). Keep the file somewhere safe.",
+                        if n == 1 { "" } else { "s" },
+                        bytes / 1e6
+                    )),
+                    Err(e) => notice(format!("Backup failed: {e}")),
+                }
+            });
+            Ok(json!({"started": true}))
+        })),
+        restore_library: Some(Box::new(move |_session: &mut Session| {
+            let Some(b) = restore_backend.clone() else { return Err("nothing is stored in this browser session (?store=memory)".into()) };
+            let frozen = frozen.clone();
+            // once the backup is in place, stop saving the old library (the page reloads)
+            safety::pick_and_restore(b, move || frozen.set(true));
+            Ok(json!({"started": true}))
+        })),
        pick_files: Some(Box::new(move || {
            open_picker(originals.clone(), backend.clone(), ctx.clone());
            Vec::new() // files arrive asynchronously and are imported on a later frame
@@ -157,6 +207,7 @@ fn services(originals: Originals, backend: Option<Backend>, ctx: egui::Context)
        // Preset files: browser pickers are asynchronous; not wired on the web yet.
        pick_preset_files: None,
        pick_tracklog: None,
+        pick_lightroom_catalog: None,
        save_preset_file: None,
        pick_curve_preset_files: None,
        save_curve_preset_file: None,
@@ -176,21 +227,29 @@ fn services(originals: Originals, backend: Option<Backend>, ctx: egui::Context)
    }
 }

-/// Write dirty library files to storage, in order, until none are left.
-async fn flush(files: Files, backend: Backend, flushing: Rc<Cell<bool>>) {
+/// Write dirty library files to storage, in order, until none are left. A failure (quota,
+/// storage cleared) is recorded in `files` — the catalog then reports changes as unsaved instead
+/// of accepting them silently — and retried after [`SAVE_RETRY_MS`].
+async fn flush(files: Files, backend: Backend, dir: String, flushing: Rc<Cell<bool>>, failed_at: Rc<Cell<f64>>) {
    'outer: loop {
        let ops = files.take_dirty();
        if ops.is_empty() {
+            if files.error().is_some() {
+                log::info!("lightcraft: saving works again");
+            }
+            files.set_error(None);
            break;
        }
        for (i, op) in ops.iter().enumerate() {
            let r = match op {
-                FlushOp::Write { name, data } => backend.write(&library_key(name), data).await,
-                FlushOp::Append { name, offset, data } => backend.write_at(&library_key(name), Some(*offset), data).await,
+                FlushOp::Write { name, data } => backend.write(&library_key(&dir, name), data).await,
+                FlushOp::Append { name, offset, data } => backend.write_at(&library_key(&dir, name), Some(*offset), data).await,
            };
            if let Err(e) = r {
                log::error!("saving {} failed: {e}", op.name());
                files.failed(&ops[i..]);
+                files.set_error(Some(e));
+                failed_at.set(perf_now());
                break 'outer;
            }
        }
@@ -204,6 +263,8 @@ struct Boot {
    backend: Option<Backend>,
    files: Files,
    index: ThumbIndex,
+    /// The library folder in storage (`library`, or a restored backup's).
+    lib_dir: String,
 }

 async fn boot(opts: Options) -> Boot {
@@ -221,15 +282,32 @@ async fn boot(opts: Options) -> Boot {
    };
    let files = Files::default();
    let mut index = ThumbIndex::default();
+    let mut lib_dir = DEFAULT_LIBRARY_DIR.to_string();
    if let Some(b) = &backend {
        if opts.reset {
-            match b.clear().await {
-                Ok(()) => log::info!("lightcraft: storage cleared (?reset)"),
-                Err(e) => log::error!("clearing storage: {e}"),
+            // everything this site keeps in the browser, photos included: never without asking
+            let ok = safety::confirm(
+                "?reset deletes the LightCraft library stored in this browser, including every imported photo. \
+                 This can't be undone. Delete it?",
+            );
+            if ok {
+                match b.clear().await {
+                    Ok(()) => log::info!("lightcraft: storage cleared (?reset)"),
+                    Err(e) => log::error!("clearing storage: {e}"),
+                }
+            } else {
+                log::info!("lightcraft: ?reset declined; storage kept");
+            }
+        }
+        // a restored backup lives in its own folder (see `backup`)
+        if let Ok(Some(d)) = b.read(ACTIVE_LIBRARY).await {
+            let d = String::from_utf8_lossy(&d).trim().to_string();
+            if valid_library_dir(&d) {
+                lib_dir = d;
            }
        }
        for name in LIBRARY_FILES {
-            match b.read(&library_key(name)).await {
+            match b.read(&library_key(&lib_dir, name)).await {
                Ok(Some(data)) => files.preload(name, data),
                Ok(None) => {}
                Err(e) => log::error!("reading {name}: {e}"),
@@ -238,7 +316,14 @@ async fn boot(opts: Options) -> Boot {
        if let Ok(Some(j)) = b.read(THUMB_INDEX).await {
            index = ThumbIndex::from_json(&j);
        }
-        crate::backend::request_persistence();
+        crate::backend::request_persistence(|granted| {
+            if !granted {
+                notice(
+                    "This browser may delete LightCraft's library when it runs short of space (persistent storage wasn't granted). \
+                     Keep your original photos elsewhere and use File ▸ Back Up Library… now and then.",
+                );
+            }
+        });
        // thumbnails stored without an index entry (index saved late, or lost): delete them
        let b2 = b.clone();
        let known: std::collections::HashSet<String> = b
@@ -266,7 +351,7 @@ async fn boot(opts: Options) -> Boot {
        index.len(),
        index.total() as f64 / 1e6
    );
-    Boot { opts, backend, files, index }
+    Boot { opts, backend, files, index, lib_dir }
 }

 struct WebApp {
@@ -276,6 +361,11 @@ struct WebApp {
    backend: Option<Backend>,
    workers: Option<Workers>,
    flushing: Rc<Cell<bool>>,
+    /// When the last save to storage failed (ms; 0 = never).
+    flush_failed_at: Rc<Cell<f64>>,
+    /// Saving stopped (a restored backup is about to replace this library: the page reloads).
+    frozen: Rc<Cell<bool>>,
+    lib_dir: String,
    bench: Option<Bench>,
    first_frame_logged: bool,
    last_save: f64,
@@ -284,13 +374,13 @@ struct WebApp {

 impl WebApp {
    fn new(cc: &eframe::CreationContext<'_>, boot: Boot) -> Self {
-        let Boot { opts, backend, files, index } = boot;
+        let Boot { opts, backend, files, index, lib_dir } = boot;
        let originals = Originals::default();
        let t = perf_now();
        let mut session = Session::new();
        originals.install(&mut session);
        let stores = LibraryStores {
-            dir: format!("browser:{}/{LIBRARY_DIR}", backend.as_ref().map_or("memory", |b| b.kind())).into(),
+            dir: format!("browser:{}/{lib_dir}", backend.as_ref().map_or("memory", |b| b.kind())).into(),
            catalog: Box::new(files.store()),
            files: Box::new(files.store()),
            on_disk: false,
@@ -319,9 +409,16 @@ impl WebApp {
                });
            }
        }
+        if backend.is_some() {
+            notice(
+                "LightCraft in the browser is experimental. Your library is kept in this browser's storage: keep your original photos \
+                 elsewhere and back up with File ▸ Back Up Library….",
+            );
+        }
        // previews are large (≤ 2560 px, f32): keep few in a 32-bit address space
        session.media.preview_capacity = 3;
-        let mut app = LightcraftApp::new(session, services(originals.clone(), backend.clone(), cc.egui_ctx.clone()));
+        let frozen = Rc::new(Cell::new(false));
+        let mut app = LightcraftApp::new(session, services(originals.clone(), backend.clone(), files.clone(), frozen.clone(), cc.egui_ctx.clone()));
        let ui_written = files.get("ui.json").unwrap_or_default();
        if let Ok(ui) = serde_json::from_slice::<UiState>(&ui_written) {
            app.ui = ui;
@@ -332,8 +429,18 @@ impl WebApp {
            let cores = window().map_or(1, |w| w.navigator().hardware_concurrency() as usize);
            cores.saturating_sub(1).clamp(1, 4)
        });
-        let workers =
-            (n > 0).then(|| Workers::start(n, backend.as_ref().map_or("memory", |b| b.kind()), backend.clone(), index, cc.egui_ctx.clone()));
+        let cache = app.session.media.rendered.clone();
+        let workers = (n > 0).then(|| {
+            Workers::start(
+                n,
+                backend.as_ref().map_or("memory", |b| b.kind()),
+                backend.clone(),
+                index,
+                &cache,
+                app.session.cache_bytes(),
+                cc.egui_ctx.clone(),
+            )
+        });
        if let Some(w) = &workers {
            app.renderer.set_offload(Box::new(w.clone()));
        }
@@ -347,6 +454,9 @@ impl WebApp {
            backend,
            workers,
            flushing: Rc::new(Cell::new(false)),
+            flush_failed_at: Rc::new(Cell::new(0.0)),
+            frozen,
+            lib_dir,
            bench: opts.bench.then(|| Bench::new(origin)),
            first_frame_logged: false,
            last_save: 0.0,
@@ -408,6 +518,9 @@ impl WebApp {

    /// Save view state, UI prefs and the thumbnail index now and then; flush dirty files.
    fn save(&mut self) {
+        if self.frozen.get() {
+            return;
+        }
        let now = perf_now();
        if now - self.last_save >= SAVE_EVERY_MS {
            self.last_save = now;
@@ -429,12 +542,16 @@ impl WebApp {
                });
            }
        }
+        // after a failure, retry every couple of seconds rather than every frame
+        let backing_off = self.files.error().is_some() && now - self.flush_failed_at.get() < SAVE_RETRY_MS;
        if let Some(b) = &self.backend
            && self.files.is_dirty()
            && !self.flushing.get()
+            && !backing_off
        {
            self.flushing.set(true);
-            wasm_bindgen_futures::spawn_local(flush(self.files.clone(), b.clone(), self.flushing.clone()));
+            let (files, dir, flushing, failed_at) = (self.files.clone(), self.lib_dir.clone(), self.flushing.clone(), self.flush_failed_at.clone());
+            wasm_bindgen_futures::spawn_local(flush(files, b.clone(), dir, flushing, failed_at));
        }
    }
 }
@@ -464,8 +581,10 @@ impl WebApp {
        let (orig_n, orig_bytes) = self.originals.usage();
        json!({
            "storage": self.backend.as_ref().map_or("memory", |b| b.kind()),
+            "library": self.lib_dir,
            "dirty": self.files.is_dirty(),
            "flushing": self.flushing.get(),
+            "saveError": self.files.error(),
            "workers": {"alive": alive, "ready": ready, "remoteJobs": remote, "inlineJobs": inline},
            "originalsInMemory": orig_n,
            "originalBytesInMemory": orig_bytes,
@@ -490,9 +609,18 @@ impl WebApp {

 impl eframe::App for WebApp {
    fn logic(&mut self, ctx: &egui::Context, _frame: &mut eframe::Frame) {
+        for text in safety::take_notices() {
+            let now = ctx.input(|i| i.time);
+            self.app.ui.toast = Some((text, now + NOTICE_SECS, None));
+        }
        self.run_inbox();
        self.import_dropped(ctx);
        self.load_originals(ctx);
+        if let Some(w) = &self.workers {
+            // `library.preferences ▸ cacheMb` is read by the session; the worker index prunes on
+            // its own thread, so it gets the budget every frame and applies it on the next store.
+            w.set_budget(self.app.session.cache_bytes());
+        }
        self.app.logic(ctx);
        self.save();
        if let Some(b) = self.bench.as_mut()
@@ -527,9 +655,18 @@ impl eframe::App for WebApp {
 #[wasm_bindgen]
 pub fn start() {
    eframe::WebLogger::init(log::LevelFilter::Info).ok();
+    safety::install_panic_hook();
    log::info!("lightcraft: wasm instantiated at {:.0} ms", perf_now());
    let opts = Options::from_url();
    wasm_bindgen_futures::spawn_local(async move {
+        // one tab per library: two would each keep their own copy and overwrite each other's saves
+        if opts.store != "memory" && safety::acquire_tab_lock().await == Some(false) {
+            safety::show_blocking(
+                "LightCraft is already open in another tab or window of this browser.\n\n\
+                 Switch to that tab, or close it and reload this page. (Two tabs would overwrite each other's changes.)",
+            );
+            return;
+        }
        let Some(canvas) = window()
            .and_then(|w| w.document())
            .and_then(|d| d.get_element_by_id("lightcraft_canvas"))
@@ -11,14 +11,13 @@
 //! ([`ThumbIndex`]).

 use std::collections::HashMap;
-use std::sync::Arc;
+use std::sync::{Arc, Weak};

 use lightcraft_engine::catalog::Source;
 use lightcraft_engine::develop::{DevelopSettings, EmbeddedLens};
-use lightcraft_engine::media::{MediaCache, RenderJob, SourceLevel, SourceRef};
+use lightcraft_engine::media::{DecodedSource, MediaCache, RenderJob, SourceLevel, SourceRef};
 use lightcraft_engine::pipeline::{Quality, RenderRequest, Rendered, SourceInfo, StageCache};
-use lightcraft_preview::Lru;
-use lightcraft_raster::Rgb32f;
+use lightcraft_preview::{Hash128, Lru, PreviewCache};
 use serde::{Deserialize, Serialize};

 use crate::store::hash_of_path;
@@ -26,11 +25,17 @@ use crate::store::hash_of_path;
 /// One render request for a worker.
 #[derive(Clone, Debug, Serialize, Deserialize)]
 pub struct WireJob {
+    #[serde(default)]
+    pub cache_generation: u64,
+    #[serde(default)]
+    pub source_identity: Option<String>,
    pub level: SourceLevel,
    pub origin: Source,
    /// Decode the source at most this long.
    pub max_edge: usize,
    pub raw: bool,
+    #[serde(default)]
+    pub relative_wb: bool,
    pub as_shot_temp: f64,
    pub as_shot_tint: f64,
    pub lens: Option<EmbeddedLens>,
@@ -55,14 +60,17 @@ impl WireJob {
    pub fn from_job(job: &RenderJob, thumb_cached: bool, view: &str) -> WireJob {
        let max_edge = match &job.source {
            SourceRef::Demo { max_edge, .. } | SourceRef::File { max_edge, .. } => *max_edge,
-            SourceRef::Loaded(img) => img.width.max(img.height),
+            SourceRef::Loaded(img) => img.image.width.max(img.image.height),
            SourceRef::Smart { .. } => 2560,
        };
        WireJob {
+            cache_generation: job.cache_generation,
+            source_identity: job.source_key.map(|key| key.to_string()),
            level: job.level,
            origin: job.origin.clone(),
            max_edge,
            raw: job.info.raw,
+            relative_wb: job.info.relative_wb,
            as_shot_temp: job.info.as_shot_temp,
            as_shot_tint: job.info.as_shot_tint,
            lens: job.info.lens,
@@ -79,7 +87,14 @@ impl WireJob {
    }

    pub fn info(&self) -> SourceInfo {
-        SourceInfo { raw: self.raw, as_shot_temp: self.as_shot_temp, as_shot_tint: self.as_shot_tint, lens: self.lens }
+        SourceInfo {
+            raw: self.raw,
+            as_shot_temp: self.as_shot_temp,
+            as_shot_tint: self.as_shot_tint,
+            lens: self.lens,
+            relative_wb: self.relative_wb,
+            ..Default::default()
+        }
    }

    pub fn request(&self) -> RenderRequest {
@@ -99,8 +114,8 @@ impl WireJob {
    /// Identifies the decoded source this job needs.
    fn source_key(&self) -> String {
        match &self.origin {
-            Source::File { path } => format!("{}:{path}", self.max_edge),
-            Source::Demo { scene } => format!("{}:demo:{scene}", self.max_edge),
+            Source::File { path } => format!("{}:{:?}:{}:{path}", self.cache_generation, self.source_identity, self.max_edge),
+            Source::Demo { scene } => format!("{}:{:?}:{}:demo:{scene}", self.cache_generation, self.source_identity, self.max_edge),
        }
    }

@@ -119,7 +134,7 @@ const WORKER_SOURCE_BYTES: usize = 192 << 20;

 /// The synchronous part of a worker: decoded-source cache + rendering.
 pub struct WorkerCore {
-    sources: Lru<String, Arc<Rgb32f>>,
+    sources: Lru<String, DecodedSource>,
    media: MediaCache,
    stages: HashMap<String, Arc<StageCache>>,
 }
@@ -150,21 +165,25 @@ impl WorkerCore {
            Some(s) => s,
            None => {
                let src = match (&job.origin, original) {
-                    (Source::File { .. }, Some(bytes)) => Arc::new(lightcraft_engine::files::load_bytes(bytes, job.max_edge)?.0),
+                    (Source::File { .. }, Some(bytes)) => {
+                        let (image, info) = lightcraft_engine::files::load_bytes(bytes, job.max_edge)?;
+                        DecodedSource::new(Arc::new(image), Some(info))
+                    }
                    (Source::File { path }, None) => return Err(format!("{path}: original not found in browser storage")),
-                    (origin @ Source::Demo { .. }, _) => self.media.origin_ref(origin, job.max_edge).load()?,
+                    (origin @ Source::Demo { .. }, _) => self.media.origin_ref(origin, job.max_edge).load_source()?,
                };
-                let cost = src.width * src.height * 12 + 64;
+                let cost = src.image.width * src.image.height * 12 + 64;
                self.sources.insert(key, src.clone(), cost);
                src
            }
        };
+        let info = src.info_or(job.info());
        Ok(match &job.stages {
            Some(view) => {
                let st = self.stages.entry(view.clone()).or_default().clone();
-                lightcraft_engine::pipeline::render_cached(&src, &job.info(), &job.settings, &job.request(), &st)
+                lightcraft_engine::pipeline::render_cached(&src.image, &info, &job.settings, &job.request(), &st)
            }
-            None => lightcraft_engine::pipeline::render(&src, &job.info(), &job.settings, &job.request()),
+            None => lightcraft_engine::pipeline::render(&src.image, &info, &job.settings, &job.request()),
        })
    }
 }
@@ -173,6 +192,8 @@ impl WorkerCore {
 /// pruned like the native disk cache (least recently used first, down to 80 % of the budget).
 #[derive(Default, Serialize, Deserialize)]
 pub struct ThumbIndex {
+    #[serde(default)]
+    namespace: u64,
    /// hex key → (bytes, last use).
    entries: HashMap<String, (u64, u64)>,
    clock: u64,
@@ -183,6 +204,24 @@ pub struct ThumbIndex {
 }

 impl ThumbIndex {
+    pub fn namespace(&self) -> u64 {
+        self.namespace
+    }
+
+    /// A persistent new namespace prevents late old workers restoring an invalidated disk hit.
+    pub fn cache_key(&self, key: Hash128) -> String {
+        if self.namespace == 0 {
+            return key.to_string();
+        }
+        lightcraft_preview::Hasher128::new().str(&key.to_string()).str("cleared").u64(self.namespace).finish().to_string()
+    }
+
+    pub fn invalidate(&mut self) -> Vec<String> {
+        self.namespace = self.namespace.wrapping_add(1);
+        self.total = 0;
+        self.dirty = true;
+        self.entries.drain().map(|(key, _)| key).collect()
+    }
    pub fn from_json(bytes: &[u8]) -> ThumbIndex {
        let mut i: ThumbIndex = serde_json::from_slice(bytes).unwrap_or_default();
        i.total = i.entries.values().map(|e| e.0).sum();
@@ -260,11 +299,55 @@ impl ThumbIndex {
    }
 }

+/// Which rendered-thumbnail cache, at which generation, the stored thumbnails ([`ThumbIndex`])
+/// belong to (main thread). Clearing the previews bumps the cache's generation, and opening
+/// another library replaces the cache: either makes every stored thumbnail obsolete.
+pub struct CacheWatch(Option<(Weak<PreviewCache>, u64)>);
+
+impl CacheWatch {
+    /// Watch `active`, the session's cache when the workers start: the persisted index belongs
+    /// to it at its current generation. (Without this baseline, the first observation after a
+    /// clear would only record the cleared generation and keep the obsolete thumbnails.)
+    pub fn new(active: &Arc<PreviewCache>) -> CacheWatch {
+        CacheWatch(Some((Arc::downgrade(active), active.generation())))
+    }
+
+    /// The watched cache, while it's alive.
+    pub fn cache(&self) -> Option<Arc<PreviewCache>> {
+        self.0.as_ref().and_then(|(cache, _)| cache.upgrade())
+    }
+
+    /// `cache` at `generation` is the active one now. If it was cleared or replaced since the
+    /// last observation, invalidate `index` and return the keys whose files should be deleted.
+    pub fn observe(&mut self, cache: &Arc<PreviewCache>, generation: u64, index: &mut ThumbIndex) -> Vec<String> {
+        let changed = self.0.as_ref().is_some_and(|(old, g)| old.as_ptr() != Arc::as_ptr(cache) || *g != generation);
+        self.0 = Some((Arc::downgrade(cache), generation));
+        if changed { index.invalidate() } else { Vec::new() }
+    }
+}
+
 #[cfg(test)]
 mod tests {
    use super::*;
    use lightcraft_engine::Session;

+    #[test]
+    fn clearing_index_changes_disk_namespace_and_survives_restart() {
+        let key = lightcraft_preview::hash_bytes(b"thumbnail");
+        let mut index = ThumbIndex::default();
+        let old = index.cache_key(key);
+        assert_eq!(old, key.to_string());
+        index.insert(&old, 100);
+        assert_eq!(index.invalidate(), vec![old.clone()]);
+        let new = index.cache_key(key);
+        assert_ne!(old, new);
+        index.insert(&new, 100);
+        let reopened = ThumbIndex::from_json(&index.to_json());
+        assert_eq!(reopened.cache_key(key), new);
+        assert!(!reopened.contains(&old));
+        assert!(reopened.contains(&new));
+    }
+
    #[test]
    fn wire_job_renders_like_the_engine() {
        let mut s = Session::with_demo();
@@ -291,10 +374,13 @@ mod tests {
        let hash = crate::store::content_hash(&bytes);
        let origin = Source::File { path: crate::store::original_path(&hash, "a.png") };
        let job = WireJob {
+            cache_generation: 0,
+            source_identity: None,
            level: SourceLevel::Thumb,
            origin,
            max_edge: 512,
            raw: false,
+            relative_wb: false,
            as_shot_temp: 6500.0,
            as_shot_tint: 0.0,
            lens: None,
@@ -314,6 +400,68 @@ mod tests {
        let r = core.render(&job, Some(&bytes)).unwrap();
        assert_eq!(r.image.width, 32);
        assert_eq!(core.needs_original(&job), None, "decoded source is kept");
+        let mut reloaded = job.clone();
+        reloaded.source_identity = Some("changed content".into());
+        assert_eq!(core.needs_original(&reloaded).as_deref(), Some(hash.as_str()), "content reload must not reuse an old decoded source");
+        let mut refreshed = job.clone();
+        refreshed.cache_generation = 1;
+        assert_eq!(core.needs_original(&refreshed).as_deref(), Some(hash.as_str()), "explicit refresh must not reuse the old decoded source");
+    }
+
+    /// The persisted index as a restarted page loads it: one stored thumbnail.
+    fn persisted_index(key: Hash128) -> (ThumbIndex, String) {
+        let mut index = ThumbIndex::default();
+        let hex = index.cache_key(key);
+        index.insert(&hex, 100);
+        (ThumbIndex::from_json(&index.to_json()), hex)
+    }
+
+    #[test]
+    fn clearing_previews_before_the_first_request_invalidates_stored_thumbnails() {
+        let key = lightcraft_preview::hash_bytes(b"thumbnail");
+        let (mut index, old) = persisted_index(key);
+        let cache = Arc::new(PreviewCache::memory(1 << 20));
+        let mut watch = CacheWatch::new(&cache);
+        let mut gone = Vec::new();
+        // each frame (`Workers::finished`) observes the watched cache, even with no requests
+        let mut frame = |watch: &mut CacheWatch, index: &mut ThumbIndex| {
+            if let Some(c) = watch.cache() {
+                gone.extend(watch.observe(&c, c.generation(), index));
+            }
+        };
+        frame(&mut watch, &mut index); // an empty filtered view: no render request yet
+        cache.clear(); // File ▸ Clear Preview Cache
+        frame(&mut watch, &mut index);
+        // the filter is removed: the first thumbnail request (`Workers::try_start`)
+        gone.extend(watch.observe(&cache, cache.generation(), &mut index));
+        let disk_key = index.cache_key(key);
+        assert!(!index.touch(&disk_key), "the pre-clear thumbnail must not be read back");
+        assert_eq!(gone, vec![old.clone()], "the stored file is deleted");
+        assert_ne!(disk_key, old, "a fresh namespace: a late old write can't come back");
+        assert!(index.dirty, "the invalidated index is saved");
+    }
+
+    #[test]
+    fn replacing_the_cache_before_the_first_request_invalidates_stored_thumbnails() {
+        let key = lightcraft_preview::hash_bytes(b"thumbnail");
+        let (mut index, old) = persisted_index(key);
+        let first = Arc::new(PreviewCache::memory(1 << 20));
+        let mut watch = CacheWatch::new(&first);
+        let other = Arc::new(PreviewCache::memory(1 << 20)); // another library, generation 0 again
+        assert_eq!(watch.observe(&other, other.generation(), &mut index), vec![old]);
+    }
+
+    #[test]
+    fn a_normal_start_keeps_stored_thumbnails() {
+        let key = lightcraft_preview::hash_bytes(b"thumbnail");
+        let (mut index, old) = persisted_index(key);
+        let cache = Arc::new(PreviewCache::memory(1 << 20));
+        let mut watch = CacheWatch::new(&cache);
+        for _ in 0..3 {
+            assert!(watch.observe(&cache, cache.generation(), &mut index).is_empty());
+        }
+        assert_eq!(index.cache_key(key), old);
+        assert!(index.touch(&old), "persisted thumbnails survive a restart");
    }

    #[test]
@@ -18,7 +18,7 @@ use std::sync::Arc;

 use js_sys::{Array, Object, Reflect, Uint8Array, Uint32Array};
 use lightcraft_engine::catalog::PhotoId;
-use lightcraft_engine::media::{DISK_CACHE_BYTES, RenderJob, RenderResult, SourceLevel};
+use lightcraft_engine::media::{RenderJob, RenderResult, SourceLevel};
 use lightcraft_engine::pipeline::Rendered;
 use lightcraft_preview::{Hash128, PreviewCache};
 use lightcraft_raster::{Histogram, Rgba8};
@@ -27,7 +27,7 @@ use wasm_bindgen::JsCast;
 use wasm_bindgen::prelude::*;

 use crate::backend::Backend;
-use crate::wire::{ThumbIndex, WireJob, WorkerCore, thumb_storage_key};
+use crate::wire::{CacheWatch, ThumbIndex, WireJob, WorkerCore, thumb_storage_key};

 /// Storage key of the thumbnail index.
 pub const THUMB_INDEX: &str = "thumbs/index.json";
@@ -155,6 +155,10 @@ async fn handle(scope: &web_sys::DedicatedWorkerGlobalScope, backend: Option<Bac
 // main side

 struct Busy {
+    disk_key: Option<String>,
+    namespace: u64,
+    request_id: u64,
+    cache_generation: u64,
    id: u32,
    slot: Slot,
    photo: PhotoId,
@@ -171,12 +175,17 @@ struct W {
 }

 struct Inner {
+    /// The rendered-thumbnail cache the stored thumbnails belong to.
+    preview_generation: CacheWatch,
    workers: Vec<W>,
    done: Vec<(Slot, RenderResult, f64)>,
    next_id: u32,
    /// (photo, level) → worker that last decoded it.
    affinity: HashMap<(PhotoId, SourceLevel), usize>,
    index: ThumbIndex,
+    /// The session's thumbnail cache budget in bytes. Kept here because the prune happens on a
+    /// worker message, where the session is out of reach; the app refreshes it every frame.
+    budget: u64,
    backend: Option<Backend>,
    ctx: egui::Context,
    /// Jobs finished by workers / inline (for diagnostics).
@@ -185,19 +194,46 @@ struct Inner {
    inline_this_frame: bool,
 }

+impl Inner {
+    fn observe_cache(&mut self, cache: &Arc<PreviewCache>, generation: u64) {
+        let gone = self.preview_generation.observe(cache, generation, &mut self.index);
+        if !gone.is_empty()
+            && let Some(backend) = self.backend.clone()
+        {
+            wasm_bindgen_futures::spawn_local(async move {
+                for key in gone {
+                    let _ = backend.remove(&thumb_storage_key(&key)).await;
+                }
+            });
+        }
+    }
+}
+
 /// The main thread's handle on the render workers.
 #[derive(Clone)]
 pub struct Workers(Rc<RefCell<Inner>>);

 impl Workers {
    /// Start `n` workers (none: every job runs inline). `store` is the backend kind for workers.
-    pub fn start(n: usize, store: &str, backend: Option<Backend>, index: ThumbIndex, ctx: egui::Context) -> Workers {
+    /// `index` lists the stored thumbnails of `cache`, the session's rendered-thumbnail cache
+    /// now: watching it from the start, a clear before the first render request still counts.
+    pub fn start(
+        n: usize,
+        store: &str,
+        backend: Option<Backend>,
+        index: ThumbIndex,
+        cache: &Arc<PreviewCache>,
+        budget: u64,
+        ctx: egui::Context,
+    ) -> Workers {
        let w = Workers(Rc::new(RefCell::new(Inner {
+            preview_generation: CacheWatch::new(cache),
            workers: Vec::new(),
            done: Vec::new(),
            next_id: 0,
            affinity: HashMap::new(),
            index,
+            budget,
            backend,
            ctx,
            remote_done: 0,
@@ -248,7 +284,16 @@ impl Workers {
            w.dead = true;
            w.worker.terminate();
            if let Some(b) = w.busy.take() {
-                let r = RenderResult { photo: b.photo, level: b.level, key: b.key, rendered: Err(msg), loaded: None, quick: None };
+                let r = RenderResult {
+                    request_id: b.request_id,
+                    source_key: None,
+                    photo: b.photo,
+                    level: b.level,
+                    key: b.key,
+                    rendered: Err(msg),
+                    loaded: None,
+                    quick: None,
+                };
                g.done.push((b.slot, r, 0.0));
            }
        }
@@ -284,16 +329,21 @@ impl Workers {
        };
        if let Ok(r) = &rendered
            && let Some((cache, key)) = &b.cache
+            && cache.generation() == b.cache_generation
+            && b.namespace == g.index.namespace()
        {
-            cache.put(*key, Arc::new(r.image.clone()));
-            let hex = key.to_string();
+            cache.put_at(b.cache_generation, *key, Arc::new(r.image.clone()));
+            let hex = b.disk_key.clone().unwrap_or_else(|| key.to_string());
            let stored = get(&data, "stored").as_f64().unwrap_or(0.0) as u64;
            if get(&data, "cacheMiss").is_truthy() {
                g.index.remove(&hex);
            }
            if stored > 0 {
                g.index.insert(&hex, stored);
-                let gone = g.index.prune(DISK_CACHE_BYTES);
+                // The session's own budget (`library.preferences ▸ cacheMb`), not the native
+                // default: the browser accepted the setting, so it has to be the one enforced
+                // (#245).
+                let gone = g.index.prune(g.budget);
                if !gone.is_empty()
                    && let Some(be) = g.backend.clone()
                {
@@ -307,8 +357,31 @@ impl Workers {
            }
        }
        g.affinity.insert((b.photo, b.level), i);
+        // A cleared worker may finish writing after the initial deletion. Its old namespace
+        // is never reused, so removing this file cannot delete a replacement's cache entry.
+        if let Some((cache, _)) = &b.cache
+            && (cache.generation() != b.cache_generation || b.namespace != g.index.namespace())
+            && let (Some(backend), Some(key)) = (g.backend.clone(), b.disk_key.clone())
+        {
+            wasm_bindgen_futures::spawn_local(async move {
+                let _ = backend.remove(&thumb_storage_key(&key)).await;
+            });
+        }
        g.remote_done += 1;
-        g.done.push((b.slot, RenderResult { photo: b.photo, level: b.level, key: b.key, rendered, loaded: None, quick: None }, ms));
+        g.done.push((
+            b.slot,
+            RenderResult {
+                request_id: b.request_id,
+                source_key: None,
+                photo: b.photo,
+                level: b.level,
+                key: b.key,
+                rendered,
+                loaded: None,
+                quick: None,
+            },
+            ms,
+        ));
    }

    /// The thumbnail index as JSON if it changed since the last call (the host saves it).
@@ -328,19 +401,30 @@ impl Workers {
        let ready = g.workers.iter().filter(|w| w.ready && !w.dead).count();
        (alive, ready, g.remote_done, g.inline_done)
    }
+
+    /// The budget the thumbnail index is pruned to. The app refreshes it from the session every
+    /// frame, so `library.preferences ▸ cacheMb` applies to the next stored thumbnail.
+    pub fn set_budget(&self, bytes: u64) {
+        self.0.borrow_mut().budget = bytes;
+    }
 }

 impl RenderOffload for Workers {
    fn try_start(&mut self, slot: Slot, job: RenderJob) -> Option<RenderJob> {
        let mut g = self.0.borrow_mut();
        let g = &mut *g;
+        if let Some((cache, _)) = job.cache.as_ref().or(job.view_cache.as_ref()) {
+            g.observe_cache(cache, job.cache_generation);
+        }
        // rendered thumbnail in memory: no worker needed
        if let Some((cache, key)) = &job.cache
-            && let Some(img) = cache.get(*key)
+            && let Some(img) = cache.get_at(job.cache_generation, *key)
        {
            let image = Arc::unwrap_or_clone(img);
            let histogram = Histogram::of_srgb8(&image);
            let r = RenderResult {
+                request_id: job.request_id,
+                source_key: job.source_key,
                photo: job.photo,
                level: job.level,
                key: job.key,
@@ -374,25 +458,45 @@ impl RenderOffload for Workers {
        let Some(i) = pick else { return Some(job) };
        // decided here, so the next job for this photo follows even before this one finishes
        g.affinity.insert((job.photo, job.level), i);
-        let thumb_cached = job.cache.as_ref().is_some_and(|(_, k)| g.index.touch(&k.to_string()));
-        let wire = WireJob::from_job(&job, thumb_cached, &format!("{slot:?}"));
+        let disk_key = job.cache.as_ref().map(|(_, key)| g.index.cache_key(*key));
+        let thumb_cached = disk_key.as_ref().is_some_and(|key| g.index.touch(key));
+        let mut wire = WireJob::from_job(&job, thumb_cached, &format!("{slot:?}"));
+        // The namespace also changes when a new library's cache starts again at generation zero.
+        wire.cache_generation = g.index.namespace();
+        wire.thumb = disk_key.clone();
        let Ok(text) = serde_json::to_string(&wire) else { return Some(job) };
        g.next_id = g.next_id.wrapping_add(1);
        let id = g.next_id;
        let msg = Object::new();
        set(&msg, "id", &id.into());
        set(&msg, "job", &text.into());
+        let namespace = g.index.namespace();
        let w = &mut g.workers[i];
        if let Err(e) = w.worker.post_message(&msg) {
            log::warn!("render worker {i}: {e:?}");
            return Some(job);
        }
-        w.busy = Some(Busy { id, slot, photo: job.photo, level: job.level, key: job.key, cache: job.cache });
+        w.busy = Some(Busy {
+            disk_key,
+            namespace,
+            request_id: job.request_id,
+            cache_generation: job.cache_generation,
+            id,
+            slot,
+            photo: job.photo,
+            level: job.level,
+            key: job.key,
+            cache: job.cache,
+        });
        None
    }

    fn finished(&mut self) -> Vec<(Slot, RenderResult, f64)> {
        let mut g = self.0.borrow_mut();
+        // Persist invalidation even when the cleared library has no visible render requests.
+        if let Some(cache) = g.preview_generation.cache() {
+            g.observe_cache(&cache, cache.generation());
+        }
        g.inline_this_frame = false;
        std::mem::take(&mut g.done)
    }
@@ -10,7 +10,7 @@ default-run = "lightcraft"
 workspace = true

 [dependencies]
-lightcraft-engine = { workspace = true }
+lightcraft-engine = { workspace = true, features = ["sam"] }
 lightcraft-sysmem = { workspace = true }
 lightcraft-ui-egui = { workspace = true }
 lightcraft-codecs = { workspace = true }
@@ -28,11 +28,11 @@ pub fn start(port: u16, ctx: egui::Context) -> Receiver<ControlRequest> {
    let listener = match TcpListener::bind(("127.0.0.1", port)) {
        Ok(l) => l,
        Err(e) => {
-            eprintln!("lightcraft: control server failed to bind 127.0.0.1:{port}: {e}");
+            log::error!("control server failed to bind 127.0.0.1:{port}: {e}");
            return rx;
        }
    };
-    eprintln!("lightcraft: control server listening on 127.0.0.1:{port}");
+    log::info!("control server listening on 127.0.0.1:{port}");
    std::thread::spawn(move || accept_loop(listener, tx, ctx));
    rx
 }
@@ -0,0 +1,145 @@
+//! File-dialog filters that match extensions whatever their letter case.
+//!
+//! On Linux, `rfd` turns each extension into a `*.ext` glob for the GTK dialog and for the
+//! desktop portal (`xdg-desktop-portal` FileChooser), and both match globs case-sensitively, so
+//! a filter of `nef` hid `DSC_1234.NEF` (issue #342). Windows and macOS ignore case. Every
+//! dialog filter of the app goes through [`FileDialogExt::add_filter_nocase`] (a test checks
+//! that nothing else calls `add_filter`), so no extension can hit this.
+
+use rfd::FileDialog;
+
+/// The patterns to hand to `rfd` for `exts`, which are plain extensions without the dot.
+///
+/// Windows and macOS take the extension literally and ignore case: lower case, de-duplicated.
+/// Linux (`linux`): `rfd` formats each entry as `*.{entry}`, which GTK 3 and the portal match
+/// as a glob, so an entry may carry glob syntax. Each extension gives the lower-case form, the
+/// UPPER-case form (kept in case a portal backend does not do `[...]` classes) and a bracket
+/// form such as `[nN][eE][fF]` that matches every mix (`.Nef`, `.nEf`, ...).
+pub fn dialog_extensions_for(exts: &[&str], linux: bool) -> Vec<String> {
+    let mut out: Vec<String> = Vec::new();
+    let mut push = |s: String| {
+        if !s.is_empty() && !out.contains(&s) {
+            out.push(s);
+        }
+    };
+    for ext in exts {
+        let ext = ext.trim_start_matches('.');
+        let lower = ext.to_lowercase();
+        push(lower.clone());
+        if !linux {
+            continue;
+        }
+        push(ext.to_uppercase());
+        // `[` `]` `*` `?` in an extension would already be glob syntax: leave those alone
+        if lower.chars().any(|c| c.is_alphabetic()) && !lower.contains(['[', ']', '*', '?', '\\']) {
+            push(
+                lower
+                    .chars()
+                    .map(|c| {
+                        let up: String = c.to_uppercase().collect();
+                        if up.chars().count() == 1 && up != c.to_string() { format!("[{c}{up}]") } else { c.to_string() }
+                    })
+                    .collect(),
+            );
+        }
+    }
+    out
+}
+
+/// [`dialog_extensions_for`] for the platform this is built for.
+pub fn dialog_extensions(exts: &[&str]) -> Vec<String> {
+    dialog_extensions_for(exts, cfg!(all(unix, not(target_os = "macos"))))
+}
+
+/// `add_filter` that matches the extensions in any letter case.
+pub trait FileDialogExt {
+    fn add_filter_nocase(self, name: impl Into<String>, exts: &[&str]) -> Self;
+}
+
+impl FileDialogExt for FileDialog {
+    fn add_filter_nocase(self, name: impl Into<String>, exts: &[&str]) -> Self {
+        self.add_filter(name, &dialog_extensions(exts))
+    }
+}
+
+#[cfg(test)]
+#[allow(clippy::unwrap_used)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn other_platforms_get_lower_case_once() {
+        assert_eq!(dialog_extensions_for(&["NEF", "nef", ".Jpg", "jpg", ""], false), ["nef", "jpg"]);
+    }
+
+    #[test]
+    fn linux_gets_lower_upper_and_any_mix() {
+        assert_eq!(dialog_extensions_for(&["nef"], true), ["nef", "NEF", "[nN][eE][fF]"]);
+        // digits have no case; a duplicate adds nothing
+        assert_eq!(dialog_extensions_for(&["mp4", "MP4"], true), ["mp4", "MP4", "[mM][pP]4"]);
+        assert_eq!(dialog_extensions_for(&["7z"], true), ["7z", "7Z", "7[zZ]"]);
+        assert_eq!(dialog_extensions_for(&["123"], true), ["123"]);
+    }
+
+    #[test]
+    fn linux_glob_syntax_is_not_wrapped_again() {
+        assert_eq!(dialog_extensions_for(&["[nN]ef"], true), ["[nn]ef", "[NN]EF"]);
+    }
+
+    /// The Linux patterns match like GTK's glob (`*.{entry}`): checked against a tiny matcher of
+    /// the subset used here (verified against real GTK 3.24 `GtkFileFilter` in the PR notes).
+    fn glob_ext(entry: &str, ext: &str) -> bool {
+        let mut pat = entry.chars().peekable();
+        let mut s = ext.chars();
+        while let Some(p) = pat.next() {
+            let Some(c) = s.next() else { return false };
+            if p == '[' {
+                let mut hit = false;
+                for q in pat.by_ref() {
+                    if q == ']' {
+                        break;
+                    }
+                    hit |= q == c;
+                }
+                if !hit {
+                    return false;
+                }
+            } else if p != c {
+                return false;
+            }
+        }
+        s.next().is_none()
+    }
+
+    #[test]
+    fn linux_patterns_match_every_case_mix() {
+        let pats = dialog_extensions_for(&["nef", "cr2", "xmp"], true);
+        let matches = |name: &str| pats.iter().any(|p| glob_ext(p, name));
+        for ok in ["nef", "NEF", "Nef", "nEF", "CR2", "Cr2", "XMP", "xMp"] {
+            assert!(matches(ok), "{ok}");
+        }
+        for bad in ["nex", "ne", "nefs", "jpg", "cr3"] {
+            assert!(!matches(bad), "{bad}");
+        }
+    }
+
+    /// The app's own extension list (the one the folder scan uses) is covered whole.
+    #[test]
+    fn import_extensions_are_all_covered_in_both_cases() {
+        let pats = dialog_extensions_for(lightcraft_engine::import::EXTENSIONS, true);
+        for e in lightcraft_engine::import::EXTENSIONS {
+            assert!(pats.iter().any(|p| glob_ext(p, &e.to_uppercase())), "{e}");
+            assert!(pats.iter().any(|p| p == e), "{e}");
+        }
+    }
+
+    /// Every dialog filter goes through the helper: `main.rs` must not call rfd's own
+    /// `add_filter`.
+    #[test]
+    fn no_dialog_bypasses_the_helper() {
+        for (file, src) in [("main.rs", include_str!("main.rs")), ("control_server.rs", include_str!("control_server.rs"))] {
+            assert!(!src.contains(".add_filter("), "{file} calls rfd's add_filter; use add_filter_nocase");
+        }
+        assert!(include_str!("main.rs").contains(".add_filter_nocase("));
+    }
+}
@@ -0,0 +1,689 @@
+//! The desktop app's logger: `log::` records go to standard error and to a log file.
+//!
+//! It replaces the stderr-only `StderrLog` that `main.rs` used to install. A launch from a
+//! desktop menu or the Dock has no terminal, so the file is what a bug report can attach:
+//! `<settings folder>/logs/lightcraft.log`, next to `ui.json` (`config_dir` in `main.rs`; Linux
+//! `$XDG_CONFIG_HOME/lightcraft/logs`, by default `~/.config/lightcraft/logs`). Never in the
+//! library folder. Each start moves the previous log to `lightcraft.1.log` (and that one to `.2`),
+//! so the log of a run that crashed survives the next launch. Runs with `LIGHTCRAFT_NO_PREFS`
+//! (tests, scripts) log to standard error only, so they don't rotate away the user's own logs.
+//!
+//! Levels ([`filter_spec`]): `info` for LightCraft's own crates, `warn` for everything else (wgpu
+//! and naga are chatty). `LIGHTCRAFT_LOG` keeps the meaning it had with the old logger: `info` or
+//! `debug` lowers LightCraft's own crates to that level, any other value means warnings and errors
+//! only. Without it, `RUST_LOG` replaces the default with env_logger-style directives: `debug`,
+//! `warn,lightcraft_pipeline=trace`, `wgpu_core=info`. A directive ending in `*` matches every
+//! target that starts with it (`lightcraft*=debug`).
+//!
+//! Records logged before the settings folder is known are kept (up to [`MAX_PENDING`]) and
+//! written once the file is attached. Writing never panics: a file that can't be created or
+//! written leaves standard error as the only sink. Panics that escape everything are added to the
+//! file by [`AppLogger::record_panic`] (the default hook already printed them on standard error).
+//!
+//! This is the desktop app's logger only; `lightcraft-cli` doesn't share a process with it.
+
+use std::fs::File;
+use std::io::Write;
+use std::path::{Path, PathBuf};
+use std::sync::{Mutex, OnceLock, PoisonError, TryLockError};
+use std::time::SystemTime;
+
+use log::LevelFilter;
+
+/// The current log file's name inside the log folder.
+pub const LOG_FILE: &str = "lightcraft.log";
+/// How many previous logs are kept (`lightcraft.1.log` … `lightcraft.<KEEP>.log`).
+pub const KEEP: usize = 2;
+/// The log file stops growing past this size (a runaway warning can't fill the disk).
+pub const MAX_FILE_BYTES: u64 = 16 * 1024 * 1024;
+/// Records kept in memory until the log file is attached.
+pub const MAX_PENDING: usize = 512;
+/// The built-in filter when neither `LIGHTCRAFT_LOG` nor `RUST_LOG` says otherwise.
+pub const DEFAULT_FILTER: &str = "warn,lightcraft*=info";
+
+/// The filter directives for this run from `LIGHTCRAFT_LOG` and `RUST_LOG` (blank = unset).
+///
+/// `LIGHTCRAFT_LOG` wins when set and means what it did for the old stderr logger: `info` or
+/// `debug` for LightCraft's own crates (warnings and errors from everything else), any other value
+/// warnings and errors only. Else `RUST_LOG` as env_logger directives, else [`DEFAULT_FILTER`].
+pub fn filter_spec(lightcraft_log: Option<&str>, rust_log: Option<&str>) -> String {
+    let set = |v: Option<&str>| v.map(str::trim).filter(|v| !v.is_empty()).map(str::to_owned);
+    if let Some(level) = set(lightcraft_log) {
+        return match level.as_str() {
+            "debug" => "warn,lightcraft*=debug".to_owned(),
+            "info" => "warn,lightcraft*=info".to_owned(),
+            _ => "warn".to_owned(),
+        };
+    }
+    set(rust_log).unwrap_or_else(|| DEFAULT_FILTER.to_owned())
+}
+
+/// Per-target level filter parsed from env_logger-style directives.
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct Filter {
+    default: LevelFilter,
+    directives: Vec<(String, LevelFilter)>,
+}
+
+impl Filter {
+    /// Parse `spec`; unknown levels and empty parts are skipped. Without a bare level, targets no
+    /// directive names log errors only.
+    pub fn parse(spec: &str) -> Filter {
+        let mut f = Filter { default: LevelFilter::Error, directives: Vec::new() };
+        for part in spec.split(',').map(str::trim).filter(|p| !p.is_empty()) {
+            match part.split_once('=') {
+                Some((name, level)) => {
+                    let name = name.trim();
+                    if let (false, Some(level)) = (name.is_empty(), parse_level(level)) {
+                        f.directives.push((name.to_owned(), level));
+                    }
+                }
+                None => match parse_level(part) {
+                    Some(level) => f.default = level,
+                    // A bare target name: everything from it (env_logger does the same).
+                    None => f.directives.push((part.to_owned(), LevelFilter::Trace)),
+                },
+            }
+        }
+        f
+    }
+
+    /// The level that applies to `target` (the most specific matching directive wins).
+    pub fn level_for(&self, target: &str) -> LevelFilter {
+        self.directives.iter().filter(|(name, _)| matches(name, target)).max_by_key(|(name, _)| name.len()).map_or(self.default, |(_, level)| *level)
+    }
+
+    /// The most verbose level any target can reach (for `log::set_max_level`).
+    pub fn max(&self) -> LevelFilter {
+        self.directives.iter().map(|(_, level)| *level).fold(self.default, Ord::max)
+    }
+}
+
+fn parse_level(s: &str) -> Option<LevelFilter> {
+    s.trim().parse().ok()
+}
+
+/// `name` matches `target` itself and its submodules (`a` matches `a` and `a::b`, not `ab`);
+/// `name*` matches every target starting with `name`.
+fn matches(name: &str, target: &str) -> bool {
+    match name.strip_suffix('*') {
+        Some(prefix) => target.starts_with(prefix),
+        None => target.strip_prefix(name).is_some_and(|rest| rest.is_empty() || rest.starts_with("::")),
+    }
+}
+
+/// `2026-10-08T07:59:17.728Z` (UTC, milliseconds). A clock before 1970 reads as the epoch.
+pub fn timestamp(t: SystemTime) -> String {
+    let since = t.duration_since(std::time::UNIX_EPOCH).unwrap_or_default();
+    let secs = since.as_secs();
+    let (days, rem) = (secs / 86_400, secs % 86_400);
+    let (y, m, d) = civil_from_days(days);
+    format!("{y:04}-{m:02}-{d:02}T{:02}:{:02}:{:02}.{:03}Z", rem / 3600, rem % 3600 / 60, rem % 60, since.subsec_millis())
+}
+
+/// Days since 1970-01-01 to a proleptic Gregorian (year, month, day) (Howard Hinnant's
+/// `civil_from_days`, unsigned because `timestamp` clamps at the epoch). Saturating, so no clock
+/// value can overflow it.
+fn civil_from_days(days: u64) -> (u64, u64, u64) {
+    let z = days.saturating_add(719_468);
+    let era = z / 146_097;
+    let doe = z % 146_097;
+    let yoe = (doe - doe / 1460 + doe / 36_524 - doe / 146_096) / 365;
+    let doy = doe - (365 * yoe + yoe / 4 - yoe / 100);
+    let mp = (5 * doy + 2) / 153;
+    let d = doy - (153 * mp + 2) / 5 + 1;
+    let m = if mp < 10 { mp + 3 } else { mp - 9 };
+    let y = era.saturating_mul(400).saturating_add(yoe).saturating_add(u64::from(m <= 2));
+    (y, m, d)
+}
+
+fn numbered(dir: &Path, n: usize) -> PathBuf {
+    if n == 0 { dir.join(LOG_FILE) } else { dir.join(format!("lightcraft.{n}.log")) }
+}
+
+/// Shift the previous logs up one (`.log` → `.1.log` → … → `.<KEEP>.log`, the oldest dropped)
+/// and create a fresh, empty log file in `dir` (created if missing).
+pub fn rotate(dir: &Path) -> std::io::Result<(PathBuf, File)> {
+    std::fs::create_dir_all(dir)?;
+    for n in (1..=KEEP).rev() {
+        match std::fs::rename(numbered(dir, n - 1), numbered(dir, n)) {
+            Err(e) if e.kind() != std::io::ErrorKind::NotFound => return Err(e),
+            _ => {}
+        }
+    }
+    let path = numbered(dir, 0);
+    let file = File::create(&path)?;
+    Ok((path, file))
+}
+
+/// One formatted log line: `<timestamp> <LEVEL> [<thread>] <target>: <message>\n`.
+pub fn format_line(ts: &str, level: log::Level, thread: &str, target: &str, message: &str) -> String {
+    let message = message.strip_suffix('\n').unwrap_or(message);
+    format!("{ts} {level:<5} [{thread}] {target}: {message}\n")
+}
+
+/// Where formatted lines go besides standard error: kept in memory until a file is attached,
+/// then appended to it until it reaches its size cap.
+pub struct Sink {
+    file: Option<File>,
+    pending: Vec<String>,
+    dropped: usize,
+    written: u64,
+    max_bytes: u64,
+    capped: bool,
+}
+
+impl Sink {
+    pub fn new(max_bytes: u64) -> Sink {
+        Sink { file: None, pending: Vec::new(), dropped: 0, written: 0, max_bytes, capped: false }
+    }
+
+    /// Append `line` to the file, or keep it until [`Sink::attach`].
+    pub fn write(&mut self, line: &str) {
+        if self.file.is_none() {
+            if self.capped {
+                // No file is coming ([`Sink::no_file`]): standard error had the line.
+            } else if self.pending.len() < MAX_PENDING {
+                self.pending.push(line.to_owned());
+            } else {
+                self.dropped = self.dropped.saturating_add(1);
+            }
+            return;
+        }
+        self.append(line);
+    }
+
+    /// Start writing to `file` (a fresh one: the size cap starts over), first the lines kept so far.
+    pub fn attach(&mut self, file: File) {
+        self.file = Some(file);
+        self.written = 0;
+        self.capped = false;
+        for line in std::mem::take(&mut self.pending) {
+            self.append(&line);
+        }
+        if self.dropped > 0 {
+            let note = format!("{} earlier log lines were dropped before the log file was opened\n", self.dropped);
+            self.dropped = 0;
+            self.append(&note);
+        }
+    }
+
+    /// There will be no log file: forget the lines kept for it and keep no more.
+    pub fn no_file(&mut self) {
+        self.file = None;
+        self.pending = Vec::new();
+        self.dropped = 0;
+        self.capped = true;
+    }
+
+    fn append(&mut self, line: &str) {
+        if self.capped {
+            return;
+        }
+        let Some(file) = self.file.as_mut() else { return };
+        let len = u64::try_from(line.len()).unwrap_or(u64::MAX);
+        let text = if self.written.saturating_add(len) > self.max_bytes {
+            self.capped = true;
+            format!("log file reached {} bytes; later records go to standard error only\n", self.max_bytes)
+        } else {
+            self.written = self.written.saturating_add(len);
+            line.to_owned()
+        };
+        // A full disk or a vanished file must not take the app down: drop the file sink.
+        if file.write_all(text.as_bytes()).is_err() {
+            self.file = None;
+            self.capped = true;
+        }
+    }
+}
+
+/// The installed logger: a [`Filter`], standard error and a [`Sink`].
+pub struct AppLogger {
+    filter: Filter,
+    stderr: bool,
+    sink: Mutex<Sink>,
+}
+
+impl AppLogger {
+    pub fn new(filter: Filter, stderr: bool) -> AppLogger {
+        AppLogger { filter, stderr, sink: Mutex::new(Sink::new(MAX_FILE_BYTES)) }
+    }
+
+    /// Rotate the logs in `dir` and send records to the fresh file; returns its path. On an error
+    /// standard error stays the only sink.
+    pub fn attach_dir(&self, dir: &Path) -> Result<PathBuf, String> {
+        // A thread that panicked while logging leaves the sink usable: take it back.
+        let mut sink = self.sink.lock().unwrap_or_else(PoisonError::into_inner);
+        match rotate(dir) {
+            Ok((path, file)) => {
+                sink.attach(file);
+                Ok(path)
+            }
+            Err(e) => {
+                sink.no_file();
+                Err(format!("{}: {e}", dir.display()))
+            }
+        }
+    }
+
+    /// No log file for this run (`LIGHTCRAFT_NO_PREFS`): log to standard error only.
+    pub fn no_file(&self) {
+        self.sink.lock().unwrap_or_else(PoisonError::into_inner).no_file();
+    }
+
+    /// Add a panic report to the log file only (the default panic hook has printed it on standard
+    /// error), whatever the filter. Skipped when the sink is busy: the panic may have happened on
+    /// this very thread while it held the lock, and waiting would hang the app.
+    pub fn record_panic(&self, thread: &str, report: &str) {
+        let line = format_line(&timestamp(SystemTime::now()), log::Level::Error, thread, "lightcraft", report);
+        let mut sink = match self.sink.try_lock() {
+            Ok(sink) => sink,
+            Err(TryLockError::Poisoned(p)) => p.into_inner(),
+            Err(TryLockError::WouldBlock) => return,
+        };
+        sink.write(&line);
+    }
+}
+
+impl log::Log for AppLogger {
+    fn enabled(&self, metadata: &log::Metadata<'_>) -> bool {
+        metadata.level() <= self.filter.level_for(metadata.target())
+    }
+
+    fn log(&self, record: &log::Record<'_>) {
+        if !self.enabled(record.metadata()) {
+            return;
+        }
+        // Formatted before the sink is locked, so a message that logs while it is formatted can't deadlock.
+        let thread = std::thread::current();
+        let line =
+            format_line(&timestamp(SystemTime::now()), record.level(), thread.name().unwrap_or("?"), record.target(), &record.args().to_string());
+        if self.stderr {
+            // No terminal (a Windows GUI build, a closed pipe) is not an error worth reporting.
+            let _ = std::io::stderr().write_all(line.as_bytes());
+        }
+        self.sink.lock().unwrap_or_else(PoisonError::into_inner).write(&line);
+    }
+
+    fn flush(&self) {}
+}
+
+/// Install the logger (filter from [`filter_spec`]); `None` when another logger was installed
+/// first. Call [`AppLogger::attach_dir`] (or [`AppLogger::no_file`]) once the arguments are parsed.
+pub fn install() -> Option<&'static AppLogger> {
+    static LOGGER: OnceLock<AppLogger> = OnceLock::new();
+    let var = |name| std::env::var(name).ok();
+    let filter = Filter::parse(&filter_spec(var("LIGHTCRAFT_LOG").as_deref(), var("RUST_LOG").as_deref()));
+    let max = filter.max();
+    let logger = LOGGER.get_or_init(|| AppLogger::new(filter, true));
+    log::set_logger(logger).ok()?;
+    log::set_max_level(max);
+    Some(logger)
+}
+
+/// Chain a panic hook after the current one (the engine guard's: standard error plus
+/// `lightcraft-panics.log` in the temp folder) that also puts the panic in the log file.
+pub fn record_panics(logger: &'static AppLogger) {
+    let previous = std::panic::take_hook();
+    std::panic::set_hook(Box::new(move |info| {
+        previous(info);
+        let thread = std::thread::current();
+        let at = info.location().map(|l| format!(" at {}:{}", l.file(), l.line())).unwrap_or_default();
+        let report = format!("panic{at}: {}", lightcraft_engine::guard::panic_message(info.payload()));
+        logger.record_panic(thread.name().unwrap_or("?"), &report);
+    }));
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::sync::atomic::{AtomicUsize, Ordering};
+    use std::time::{Duration, UNIX_EPOCH};
+
+    fn temp_dir(tag: &str) -> PathBuf {
+        static N: AtomicUsize = AtomicUsize::new(0);
+        let d = std::env::temp_dir().join(format!("lightcraft-logging-{tag}-{}-{}", std::process::id(), N.fetch_add(1, Ordering::Relaxed)));
+        let _ = std::fs::remove_dir_all(&d);
+        d
+    }
+
+    fn read(path: &Path) -> String {
+        std::fs::read_to_string(path).expect("read log")
+    }
+
+    fn record(logger: &AppLogger, level: log::Level, target: &str, msg: &str) {
+        use log::Log;
+        logger.log(&log::Record::builder().level(level).target(target).args(format_args!("{msg}")).build());
+    }
+
+    /// The logger this replaced (`StderrLog`): warnings and errors from every target, `info` and
+    /// `debug` only from LightCraft's own crates, and only when `LIGHTCRAFT_LOG` asked for them.
+    fn old_stderr_log_enabled(lightcraft_log: &str, level: log::Level, target: &str) -> bool {
+        let max = match lightcraft_log {
+            "debug" => LevelFilter::Debug,
+            "info" => LevelFilter::Info,
+            _ => LevelFilter::Warn,
+        };
+        level <= max && (level <= log::Level::Warn || target.starts_with("lightcraft"))
+    }
+
+    #[test]
+    fn the_default_filter_shows_lightcraft_info_and_other_crates_warnings() {
+        let f = Filter::parse(DEFAULT_FILTER);
+        assert_eq!(f.level_for("lightcraft"), LevelFilter::Info);
+        assert_eq!(f.level_for("lightcraft::control_server"), LevelFilter::Info);
+        assert_eq!(f.level_for("lightcraft_engine::guard"), LevelFilter::Info);
+        assert_eq!(f.level_for("lightcraft_ui_egui::render"), LevelFilter::Info);
+        assert_eq!(f.level_for("wgpu_core::device"), LevelFilter::Warn);
+        assert_eq!(f.level_for("naga"), LevelFilter::Warn);
+        assert_eq!(f.max(), LevelFilter::Info);
+        assert_eq!(filter_spec(None, None), DEFAULT_FILTER);
+        // An empty variable is the same as an unset one.
+        assert_eq!(filter_spec(Some(""), Some("  ")), DEFAULT_FILTER);
+    }
+
+    /// `LIGHTCRAFT_LOG` keeps working exactly as it did with the old stderr-only logger.
+    #[test]
+    fn lightcraft_log_keeps_its_meaning() {
+        let targets =
+            ["lightcraft", "lightcraft::control_server", "lightcraft_engine::segment", "lightcraft_gpu", "wgpu_core::device", "naga", "eframe"];
+        let levels = [log::Level::Error, log::Level::Warn, log::Level::Info, log::Level::Debug, log::Level::Trace];
+        for value in ["info", "debug", "warn", "error", "verbose", "INFO"] {
+            let f = Filter::parse(&filter_spec(Some(value), None));
+            for target in targets {
+                for level in levels {
+                    assert_eq!(level <= f.level_for(target), old_stderr_log_enabled(value, level, target), "LIGHTCRAFT_LOG={value} {level} {target}");
+                }
+            }
+        }
+        assert_eq!(Filter::parse(&filter_spec(Some("debug"), None)).max(), LevelFilter::Debug);
+        assert_eq!(Filter::parse(&filter_spec(Some("warn"), None)).max(), LevelFilter::Warn);
+    }
+
+    #[test]
+    fn rust_log_replaces_the_default_and_lightcraft_log_wins_over_it() {
+        assert_eq!(filter_spec(None, Some("warn,wgpu_core=info")), "warn,wgpu_core=info");
+        let f = Filter::parse(&filter_spec(None, Some("debug")));
+        assert_eq!(f.level_for("eframe"), LevelFilter::Debug);
+        // The app's own variable is the more specific choice.
+        let f = Filter::parse(&filter_spec(Some("info"), Some("trace")));
+        assert_eq!(f.level_for("eframe"), LevelFilter::Warn);
+        assert_eq!(f.level_for("lightcraft_engine"), LevelFilter::Info);
+    }
+
+    #[test]
+    fn directives_follow_env_logger_and_the_most_specific_one_wins() {
+        let f = Filter::parse("info,wgpu_core=error,lightcraft_pipeline=trace,lightcraft_pipeline::tiles=off");
+        assert_eq!(f.level_for("eframe"), LevelFilter::Info);
+        assert_eq!(f.level_for("wgpu_core::instance"), LevelFilter::Error);
+        assert_eq!(f.level_for("lightcraft_pipeline::stage"), LevelFilter::Trace);
+        assert_eq!(f.level_for("lightcraft_pipeline::tiles"), LevelFilter::Off);
+        assert_eq!(f.max(), LevelFilter::Trace);
+        // A module name is matched at `::` boundaries, not as a bare prefix.
+        assert_eq!(f.level_for("wgpu_core_extra"), LevelFilter::Info);
+        // A trailing `*` is a prefix.
+        assert_eq!(Filter::parse("lightcraft*=debug").level_for("lightcraft_raw::cr2"), LevelFilter::Debug);
+        assert_eq!(Filter::parse("lightcraft*=debug").level_for("eframe"), LevelFilter::Error);
+        // A bare target name sets that target to the most verbose level, as env_logger does.
+        assert_eq!(Filter::parse("naga").level_for("naga::front"), LevelFilter::Trace);
+        assert_eq!(Filter::parse("naga").level_for("eframe"), LevelFilter::Error);
+        // Levels are case-insensitive and surrounding blanks are ignored.
+        assert_eq!(Filter::parse(" WARN , lightcraft = Debug ").level_for("lightcraft"), LevelFilter::Debug);
+        assert_eq!(Filter::parse(" WARN , lightcraft = Debug ").level_for("eframe"), LevelFilter::Warn);
+    }
+
+    #[test]
+    fn hostile_specs_never_panic_and_fall_back_sensibly() {
+        let long = "x".repeat(100_000);
+        let many = "a=info,".repeat(10_000);
+        for spec in [
+            "",
+            ",,,",
+            "=",
+            "==",
+            "=debug",
+            "lightcraft=",
+            "nonsense=loud",
+            "🦀=info",
+            "*",
+            "*=",
+            "=*",
+            "a=b=c",
+            "warn,,lightcraft=DEBUG",
+            "\0",
+            "é::ü=trace",
+            &long,
+            &many,
+        ] {
+            let f = Filter::parse(spec);
+            for target in ["", "lightcraft", "🦀", "a::b", "*"] {
+                let _ = f.level_for(target);
+            }
+            let _ = f.max();
+            let _ = filter_spec(Some(spec), Some(spec));
+        }
+        assert_eq!(Filter::parse("warn,,lightcraft=DEBUG").level_for("lightcraft"), LevelFilter::Debug);
+        // An unknown level is skipped: that target keeps the default.
+        assert_eq!(Filter::parse("nonsense=loud").level_for("nonsense"), LevelFilter::Error);
+        assert_eq!(Filter::parse("lightcraft=").level_for("lightcraft"), LevelFilter::Error);
+        assert_eq!(Filter::parse("=debug").max(), LevelFilter::Error);
+        assert_eq!(Filter::parse("🦀=info").level_for("🦀::claw"), LevelFilter::Info);
+    }
+
+    #[test]
+    fn timestamps_are_utc_with_milliseconds() {
+        assert_eq!(timestamp(UNIX_EPOCH), "1970-01-01T00:00:00.000Z");
+        assert_eq!(timestamp(UNIX_EPOCH + Duration::from_millis(1_791_446_357_728)), "2026-10-08T07:59:17.728Z");
+        // Leap day, and the day after it.
+        assert_eq!(timestamp(UNIX_EPOCH + Duration::from_secs(1_709_164_800)), "2024-02-29T00:00:00.000Z");
+        assert_eq!(timestamp(UNIX_EPOCH + Duration::from_secs(1_709_251_199)), "2024-02-29T23:59:59.000Z");
+        assert_eq!(timestamp(UNIX_EPOCH + Duration::from_secs(1_709_251_200)), "2024-03-01T00:00:00.000Z");
+        // 2000 is a leap year (divisible by 400), 2100 is not.
+        assert_eq!(timestamp(UNIX_EPOCH + Duration::from_secs(951_782_400)), "2000-02-29T00:00:00.000Z");
+        assert_eq!(timestamp(UNIX_EPOCH + Duration::from_secs(4_107_542_400)), "2100-03-01T00:00:00.000Z");
+        // Before the epoch (a clock set wrong) clamps instead of panicking.
+        assert_eq!(timestamp(UNIX_EPOCH - Duration::from_secs(5)), "1970-01-01T00:00:00.000Z");
+    }
+
+    #[test]
+    fn a_line_carries_time_level_thread_target_and_message() {
+        assert_eq!(
+            format_line("2026-10-08T07:59:17.728Z", log::Level::Info, "main", "lightcraft", "library /photos: 12 photos"),
+            "2026-10-08T07:59:17.728Z INFO  [main] lightcraft: library /photos: 12 photos\n"
+        );
+        // A multi-line message keeps its lines; the record still ends in one newline.
+        assert!(format_line("t", log::Level::Error, "w", "x", "a\nb\n").ends_with("x: a\nb\n"));
+    }
+
+    #[test]
+    fn rotation_keeps_the_previous_logs_and_starts_an_empty_file() {
+        let dir = temp_dir("rotate");
+        for run in 1..=4 {
+            let (path, _file) = rotate(&dir).expect("rotate");
+            assert_eq!(path, dir.join(LOG_FILE));
+            assert_eq!(read(&path), "");
+            std::fs::write(&path, format!("run {run}")).expect("write");
+        }
+        assert_eq!(read(&dir.join(LOG_FILE)), "run 4");
+        assert_eq!(read(&dir.join("lightcraft.1.log")), "run 3");
+        assert_eq!(read(&dir.join("lightcraft.2.log")), "run 2");
+        assert!(!dir.join("lightcraft.3.log").exists(), "only {KEEP} old logs are kept");
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+
+    #[test]
+    fn rotation_into_an_unusable_directory_is_an_error_not_a_panic() {
+        let dir = temp_dir("blocked");
+        std::fs::create_dir_all(dir.parent().expect("parent")).expect("tmp");
+        std::fs::write(&dir, "a file where the directory should be").expect("block");
+        assert!(rotate(&dir).is_err());
+        let _ = std::fs::remove_file(&dir);
+    }
+
+    #[test]
+    fn lines_logged_before_the_file_exists_are_written_when_it_is_attached() {
+        let dir = temp_dir("pending");
+        let (path, file) = rotate(&dir).expect("rotate");
+        let mut sink = Sink::new(MAX_FILE_BYTES);
+        sink.write("early 1\n");
+        sink.write("early 2\n");
+        sink.attach(file);
+        sink.write("late\n");
+        assert_eq!(read(&path), "early 1\nearly 2\nlate\n");
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+
+    #[test]
+    fn the_pending_buffer_is_bounded_and_says_how_much_it_dropped() {
+        let dir = temp_dir("bounded");
+        let (path, file) = rotate(&dir).expect("rotate");
+        let mut sink = Sink::new(MAX_FILE_BYTES);
+        for i in 0..MAX_PENDING + 5 {
+            sink.write(&format!("line {i}\n"));
+        }
+        sink.attach(file);
+        let text = read(&path);
+        assert_eq!(text.lines().filter(|l| l.starts_with("line ")).count(), MAX_PENDING);
+        assert!(text.contains("5 earlier log lines were dropped"), "{text}");
+        assert!(text.contains("line 0\n") && !text.contains(&format!("line {MAX_PENDING}\n")));
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+
+    #[test]
+    fn exactly_a_full_pending_buffer_drops_nothing() {
+        let dir = temp_dir("full");
+        let (path, file) = rotate(&dir).expect("rotate");
+        let mut sink = Sink::new(MAX_FILE_BYTES);
+        for i in 0..MAX_PENDING {
+            sink.write(&format!("line {i}\n"));
+        }
+        sink.attach(file);
+        let text = read(&path);
+        assert_eq!(text.lines().count(), MAX_PENDING);
+        assert!(!text.contains("dropped"), "{text}");
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+
+    #[test]
+    fn without_a_file_nothing_is_kept_in_memory() {
+        let mut sink = Sink::new(MAX_FILE_BYTES);
+        sink.write("early\n");
+        sink.no_file();
+        sink.write("late\n");
+        assert!(sink.pending.is_empty() && sink.dropped == 0);
+    }
+
+    #[test]
+    fn the_file_stops_at_its_size_cap_with_one_note() {
+        let dir = temp_dir("cap");
+        let (path, file) = rotate(&dir).expect("rotate");
+        let mut sink = Sink::new(100);
+        sink.attach(file);
+        for i in 0..50 {
+            sink.write(&format!("line {i:02} with some padding\n"));
+        }
+        let text = read(&path);
+        assert_eq!(text.lines().filter(|l| l.starts_with("line ")).count(), 3, "{text}");
+        assert_eq!(text.matches("log file reached").count(), 1, "{text}");
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+
+    #[test]
+    fn the_logger_filters_records_and_writes_them_to_the_attached_file() {
+        use log::Log;
+        let dir = temp_dir("logger");
+        let logger = AppLogger::new(Filter::parse(DEFAULT_FILTER), false);
+        record(&logger, log::Level::Info, "lightcraft", "before the settings directory");
+        record(&logger, log::Level::Info, "wgpu_core::device", "too chatty");
+        let path = logger.attach_dir(&dir).expect("attach");
+        assert_eq!(path, dir.join(LOG_FILE));
+        record(&logger, log::Level::Warn, "wgpu_hal::vulkan", "a real warning");
+        record(&logger, log::Level::Error, "lightcraft_engine::guard", "`develop.reset` failed unexpectedly: boom");
+        record(&logger, log::Level::Debug, "lightcraft", "below info");
+        let text = read(&path);
+        let lines: Vec<&str> = text.lines().collect();
+        assert_eq!(lines.len(), 3, "{text}");
+        assert!(lines[0].contains(" INFO  [") && lines[0].ends_with("lightcraft: before the settings directory"), "{text}");
+        assert!(lines[1].ends_with("wgpu_hal::vulkan: a real warning"), "{text}");
+        assert!(lines[2].contains(" ERROR [") && lines[2].ends_with("lightcraft_engine::guard: `develop.reset` failed unexpectedly: boom"), "{text}");
+        assert!(logger.enabled(&log::Metadata::builder().level(log::Level::Info).target("lightcraft_ui_egui").build()));
+        assert!(!logger.enabled(&log::Metadata::builder().level(log::Level::Info).target("naga").build()));
+        // Attaching again rotates: the first log becomes `.1`.
+        logger.attach_dir(&dir).expect("attach again");
+        assert_eq!(read(&dir.join("lightcraft.1.log")), text);
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+
+    #[test]
+    fn records_from_many_threads_are_whole_lines() {
+        let dir = temp_dir("threads");
+        let logger = std::sync::Arc::new(AppLogger::new(Filter::parse("info"), false));
+        let path = logger.attach_dir(&dir).expect("attach");
+        let workers: Vec<_> = (0..8)
+            .map(|t| {
+                let l = std::sync::Arc::clone(&logger);
+                std::thread::spawn(move || {
+                    for i in 0..100 {
+                        record(&l, log::Level::Info, "lightcraft", &format!("thread {t} record {i}"));
+                    }
+                })
+            })
+            .collect();
+        for w in workers {
+            w.join().expect("worker");
+        }
+        let text = read(&path);
+        assert_eq!(text.lines().count(), 800);
+        assert!(text.lines().all(|l| l.contains(" lightcraft: thread ")), "{text}");
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+
+    #[test]
+    fn attaching_to_an_unusable_directory_reports_an_error_and_keeps_logging() {
+        let dir = temp_dir("unusable");
+        std::fs::create_dir_all(dir.parent().expect("parent")).expect("tmp");
+        std::fs::write(&dir, "not a directory").expect("block");
+        let logger = AppLogger::new(Filter::parse("info"), false);
+        record(&logger, log::Level::Info, "lightcraft", "early");
+        assert!(logger.attach_dir(&dir).is_err());
+        record(&logger, log::Level::Error, "x", "still fine");
+        // Nothing waits in memory for a file that won't come.
+        assert!(logger.sink.lock().expect("sink").pending.is_empty());
+        let _ = std::fs::remove_file(&dir);
+    }
+
+    #[test]
+    fn a_poisoned_sink_still_logs() {
+        let dir = temp_dir("poison");
+        let logger = std::sync::Arc::new(AppLogger::new(Filter::parse("info"), false));
+        let l = std::sync::Arc::clone(&logger);
+        let _ = std::thread::spawn(move || {
+            let _guard = l.sink.lock().expect("lock");
+            panic!("poison the sink");
+        })
+        .join();
+        assert!(logger.sink.is_poisoned());
+        let path = logger.attach_dir(&dir).expect("attach");
+        record(&logger, log::Level::Warn, "lightcraft", "after the poison");
+        assert!(read(&path).contains("lightcraft: after the poison"));
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+
+    /// The panic hook's report lands in the file, and never deadlocks when the panic happened
+    /// while this thread held the sink.
+    #[test]
+    fn a_panic_report_goes_to_the_file_and_never_deadlocks() {
+        let dir = temp_dir("panic");
+        let logger = AppLogger::new(Filter::parse("off"), false);
+        let path = logger.attach_dir(&dir).expect("attach");
+        logger.record_panic("render", "panicked at crates/x/src/lib.rs:3:5:\nboom");
+        {
+            let _held = logger.sink.lock().expect("lock");
+            logger.record_panic("main", "while the sink is held");
+        }
+        let text = read(&path);
+        assert!(text.contains(" ERROR [render] lightcraft: panicked at crates/x/src/lib.rs:3:5:\nboom\n"), "{text}");
+        assert!(!text.contains("while the sink is held"), "{text}");
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+}
@@ -24,9 +24,12 @@

 mod alloc_release;
 mod control_server;
+mod dialog_filter;
+mod logging;
 #[cfg(target_os = "macos")]
 mod native_menu;

+use dialog_filter::FileDialogExt as _;
 use lightcraft_engine::Session;
 use lightcraft_ui_egui::panels::library_problem::LibraryProblem;
 use lightcraft_ui_egui::{LightcraftApp, Services, UiState};
@@ -63,40 +66,90 @@ impl eframe::App for App {
    }
    fn on_exit(&mut self) {
        if let Err(e) = self.1.save(&self.0) {
-            eprintln!("lightcraft: {e}");
+            log::error!("{e}");
        }
        if let Err(e) = self.0.session.close_library() {
-            eprintln!("lightcraft: saving the library failed: {e}");
+            log::error!("saving the library failed: {e}");
        }
    }
 }

-fn config_dir() -> Option<std::path::PathBuf> {
-    if cfg!(target_os = "macos") {
-        std::env::var_os("HOME").map(|h| std::path::PathBuf::from(h).join("Library/Application Support/LightCraft"))
-    } else if cfg!(windows) {
-        std::env::var_os("APPDATA").map(|a| std::path::PathBuf::from(a).join("LightCraft"))
-    } else {
-        std::env::var_os("XDG_CONFIG_HOME")
-            .map(std::path::PathBuf::from)
-            .or_else(|| std::env::var_os("HOME").map(|h| std::path::PathBuf::from(h).join(".config")))
-            .map(|c| c.join("lightcraft"))
+/// The window's renderer (egui-wgpu): eframe's defaults, with LightCraft's backend choice — DX12
+/// alone on Windows unless `LIGHTCRAFT_GPU_BACKEND` / `WGPU_BACKEND` say otherwise (issue #136:
+/// with Vulkan in the set, wgpu loads the Vulkan driver even when it then picks DX12).
+fn window_wgpu_options() -> eframe::egui_wgpu::WgpuConfiguration {
+    let mut c = eframe::egui_wgpu::WgpuConfiguration::default();
+    if let eframe::egui_wgpu::WgpuSetup::CreateNew(n) = &mut c.wgpu_setup {
+        n.instance_descriptor.backends = lightcraft_engine::gpu::backend::window_backends();
    }
+    c
+}
+
+/// Written while the GPU compute device is created, removed once that returned
+/// (`lightcraft_gpu::backend::set_init_marker`). Not with `LIGHTCRAFT_NO_PREFS` (tests, scripts).
+fn gpu_marker_path() -> Option<std::path::PathBuf> {
+    if std::env::var_os("LIGHTCRAFT_NO_PREFS").is_some() {
+        return None;
+    }
+    config_dir().map(|d| d.join("gpu-init.marker"))
+}
+
+/// Arm the GPU crash sentinel; if the previous launch left it behind (it died inside the GPU
+/// driver while creating the device), the notice to show — GPU rendering then starts off.
+///
+/// A `--memory` session writes nothing (issue #169): it neither arms the sentinel — which would
+/// create the settings folder — nor removes a marker it finds. It still honours one, so the GPU
+/// starts off there too, and the next ordinary launch reports and clears it.
+fn gpu_crash_check(in_memory: bool) -> Option<String> {
+    gpu_crash_check_at(gpu_marker_path(), in_memory)
+}
+
+fn gpu_crash_check_at(marker: Option<std::path::PathBuf>, in_memory: bool) -> Option<String> {
+    use lightcraft_engine::gpu::backend;
+    let left = if in_memory {
+        marker.as_deref().and_then(backend::read_init_marker)
+    } else {
+        let left = marker.as_deref().and_then(backend::take_init_marker);
+        backend::set_init_marker(marker);
+        left
+    };
+    left.map(|what| gpu_crash_notice(&what))
+}
+
+fn gpu_crash_notice(what: &str) -> String {
+    format!(
+        "LightCraft closed unexpectedly while starting the GPU last time ({what}), so GPU rendering is now off and photos render on the CPU. \
+         To try the GPU again, turn on Settings ▸ Performance ▸ Use the GPU for rendering; to try another graphics backend, start LightCraft with \
+         LIGHTCRAFT_GPU_BACKEND=dx12, vulkan or off (see docs/gpu-pipeline.md → Troubleshooting)."
+    )
+}
+
+fn config_dir() -> Option<std::path::PathBuf> {
+    lightcraft_engine::camera_profiles::config_dir()
+}
+
+/// `<config>/ui.json`, the saved UI state and app settings — `None` when nothing is read or
+/// written: `LIGHTCRAFT_NO_PREFS` (tests, scripts) or no home folder.
+fn prefs_path() -> Option<std::path::PathBuf> {
+    if std::env::var_os("LIGHTCRAFT_NO_PREFS").is_some() {
+        return None;
+    }
+    config_dir().map(|d| d.join("ui.json"))
 }

 /// The saved UI state and app settings (`<config>/ui.json`), if any, and a warning for the user
 /// when the file exists but can't be used (issue #103): a damaged file is kept as
 /// `ui.json.corrupt-<unix time>` first, so the next save can't lose the library location in it;
 /// one that can't be read at all is not written this session (`keep_file`).
-fn load_prefs() -> (Option<UiState>, Option<String>, bool) {
-    if std::env::var_os("LIGHTCRAFT_NO_PREFS").is_some() {
-        return (None, None, false);
-    }
-    let Some(path) = config_dir().map(|d| d.join("ui.json")) else { return (None, None, false) };
-    load_prefs_at(&path)
+///
+/// A `--memory` session reads the settings (so it looks like the user's app) but writes nothing
+/// (issue #164), so a damaged file is left as it is there, not set aside.
+fn load_prefs(in_memory: bool) -> (Option<UiState>, Option<String>, bool) {
+    let Some(path) = prefs_path() else { return (None, None, false) };
+    load_prefs_at(&path, !in_memory)
 }

-fn load_prefs_at(path: &std::path::Path) -> (Option<UiState>, Option<String>, bool) {
+fn load_prefs_at(path: &std::path::Path, set_aside_damaged: bool) -> (Option<UiState>, Option<String>, bool) {
    let bytes = match std::fs::read(path) {
        Ok(b) => b,
        Err(e) if e.kind() == std::io::ErrorKind::NotFound => return (None, None, false),
@@ -107,6 +160,10 @@ fn load_prefs_at(path: &std::path::Path) -> (Option<UiState>, Option<String>, bo
    };
    match serde_json::from_slice::<UiState>(&bytes) {
        Ok(ui) => (Some(ui.sanitized()), None, false),
+        Err(e) if !set_aside_damaged => {
+            let msg = format!("The app settings ({}) are damaged ({e}). Defaults are used; nothing is saved in this session.", path.display());
+            (None, Some(msg), true)
+        }
        Err(e) => {
            let secs = std::time::SystemTime::now().duration_since(std::time::UNIX_EPOCH).map(|d| d.as_secs()).unwrap_or(0);
            let keep = path.with_file_name(format!("ui.json.corrupt-{secs}"));
@@ -149,8 +206,15 @@ fn write_atomic(path: &std::path::Path, bytes: &[u8]) -> std::io::Result<()> {

 /// Saves `ui.json` (app settings, incl. the library to open at launch): as soon as the library
 /// changes, every few seconds when anything else changed, and at exit.
+///
+/// Nothing is written while the session is one that promises to save nothing: `--memory`
+/// (`path` is `None`; issue #164), or the one running because the library couldn't be opened — the
+/// question window and Continue Without Saving (issue #100; `app.openLibrary` ends it, and the
+/// library it opened is saved then).
 #[derive(Default)]
 struct PrefsWriter {
+    /// Where to write; `None` writes nothing (`--memory`, `LIGHTCRAFT_NO_PREFS`, no home folder).
+    path: Option<std::path::PathBuf>,
    written: Vec<u8>,
    library: String,
    checked: f64,
@@ -162,19 +226,26 @@ struct PrefsWriter {

 impl PrefsWriter {
    fn save(&mut self, app: &LightcraftApp) -> Result<(), String> {
-        if self.keep_file || std::env::var_os("LIGHTCRAFT_NO_PREFS").is_some() {
+        self.save_ui(&app.ui, app.library_problem.is_some())
+    }
+
+    /// Write `ui` if it changed since the last write; `temporary` (the library couldn't be
+    /// opened) saves nothing.
+    fn save_ui(&mut self, ui: &UiState, temporary: bool) -> Result<(), String> {
+        if self.keep_file || temporary {
            return Ok(());
        }
-        let Some(d) = config_dir() else { return Ok(()) };
-        let bytes = serde_json::to_vec_pretty(&app.ui).map_err(|e| e.to_string())?;
+        let Some(path) = self.path.clone() else { return Ok(()) };
+        let bytes = serde_json::to_vec_pretty(ui).map_err(|e| e.to_string())?;
        if bytes == self.written {
            return Ok(());
        }
-        std::fs::create_dir_all(&d)
-            .and_then(|()| write_atomic(&d.join("ui.json"), &bytes))
+        path.parent()
+            .map_or(Ok(()), std::fs::create_dir_all)
+            .and_then(|()| write_atomic(&path, &bytes))
            .map_err(|e| format!("saving the app settings failed: {e}"))?;
        self.written = bytes;
-        self.library = app.ui.settings.library_path.clone();
+        self.library = ui.settings.library_path.clone();
        Ok(())
    }

@@ -188,8 +259,8 @@ impl PrefsWriter {
        match self.save(app) {
            Ok(()) => self.failing = false,
            Err(e) => {
-                eprintln!("lightcraft: {e}");
                if !self.failing {
+                    log::warn!("{e}");
                    app.notices.push(format!("{e}. LightCraft keeps trying."));
                }
                self.failing = true;
@@ -200,9 +271,28 @@ impl PrefsWriter {
    }
 }

+/// The Windows command that opens `url` in the default browser. `explorer <url>` opened File
+/// Explorer instead for links with a query or fragment, like the Map button's OpenStreetMap link
+/// (issue #234). The URL protocol handler hands the URL to the browser as is; no shell runs, so
+/// `?`, `&` and `#` need no escaping.
+fn windows_open_url_command(url: &str) -> std::process::Command {
+    let mut c = std::process::Command::new("rundll32");
+    c.args(["url.dll,FileProtocolHandler", url]);
+    c
+}
+
 fn services() -> Services {
    Services {
-        pick_folder: Some(Box::new(|| rfd::FileDialog::new().set_title("Open Library").pick_folder().map(|p| p.to_string_lossy().to_string()))),
+        pick_lightroom_catalog: Some(Box::new(|| {
+            rfd::FileDialog::new()
+                .set_title(lightcraft_ui_egui::i18n::tr("Import Lightroom Catalog"))
+                .add_filter_nocase(lightcraft_ui_egui::i18n::tr("Lightroom Classic Catalog"), &["lrcat"])
+                .pick_file()
+                .map(|p| p.to_string_lossy().to_string())
+        })),
+        pick_folder: Some(Box::new(|| {
+            rfd::FileDialog::new().set_title(lightcraft_ui_egui::i18n::tr("Open Library")).pick_folder().map(|p| p.to_string_lossy().to_string())
+        })),
        open_with: Some(Box::new(|path: &str, app: &str| {
            // spawned, never waited for: the editor runs alongside
            let app = app.trim();
@@ -232,7 +322,7 @@ fn services() -> Services {
            let status = if cfg!(target_os = "macos") {
                std::process::Command::new("open").arg(url).status()
            } else if cfg!(target_os = "windows") {
-                std::process::Command::new("explorer").arg(url).status()
+                windows_open_url_command(url).status()
            } else {
                std::process::Command::new("xdg-open").arg(url).status()
            };
@@ -242,7 +332,8 @@ fn services() -> Services {
            let status = if cfg!(target_os = "macos") {
                std::process::Command::new("open").args(["-R", path]).status()
            } else if cfg!(target_os = "windows") {
-                std::process::Command::new("explorer").arg(format!("/select,{path}")).status()
+                let win_path = path.replace('/', "\\");
+                std::process::Command::new("explorer").arg(format!("/select,{win_path}")).status()
            } else {
                let dir = std::path::Path::new(path).parent().map(|d| d.to_string_lossy().to_string()).unwrap_or_else(|| ".".into());
                std::process::Command::new("xdg-open").arg(dir).status()
@@ -253,13 +344,7 @@ fn services() -> Services {
        })),
        pick_files: Some(Box::new(|| {
            rfd::FileDialog::new()
-                .add_filter(
-                    "Photos",
-                    &[
-                        "jpg", "jpeg", "png", "tif", "tiff", "webp", "dng", "cr2", "cr3", "nef", "nrw", "arw", "raf", "orf", "rw2", "pef", "psd",
-                        "jxl", "gif", "bmp",
-                    ],
-                )
+                .add_filter_nocase(lightcraft_ui_egui::i18n::tr("Photos"), lightcraft_engine::import::EXTENSIONS)
                .pick_files()
                .unwrap_or_default()
                .into_iter()
@@ -268,8 +353,11 @@ fn services() -> Services {
        })),
        pick_preset_files: Some(Box::new(|| {
            rfd::FileDialog::new()
-                .set_title("Import Presets")
-                .add_filter("Presets & Profiles", &["lcpreset", "xmp", "lrtemplate", "zip", "dng", "lmp", "mplumpack", "cube"])
+                .set_title(lightcraft_ui_egui::i18n::tr("Import Presets"))
+                .add_filter_nocase(
+                    lightcraft_ui_egui::i18n::tr("Presets & Profiles"),
+                    &["lcpreset", "xmp", "lrtemplate", "zip", "dng", "lmp", "mplumpack", "cube"],
+                )
                .pick_files()
                .unwrap_or_default()
                .into_iter()
@@ -278,24 +366,24 @@ fn services() -> Services {
        })),
        pick_tracklog: Some(Box::new(|| {
            rfd::FileDialog::new()
-                .set_title("Auto-Tag from Tracklog")
-                .add_filter("GPS Track Log", &["gpx"])
+                .set_title(lightcraft_ui_egui::i18n::tr("Auto-Tag from Tracklog"))
+                .add_filter_nocase(lightcraft_ui_egui::i18n::tr("GPS Track Log"), &["gpx"])
                .pick_file()
                .map(|p| vec![p.to_string_lossy().to_string()])
                .unwrap_or_default()
        })),
        save_preset_file: Some(Box::new(|name: &str| {
            rfd::FileDialog::new()
-                .set_title("Export Presets")
-                .add_filter("LightCraft Preset", &["lcpreset"])
+                .set_title(lightcraft_ui_egui::i18n::tr("Export Presets"))
+                .add_filter_nocase(lightcraft_ui_egui::i18n::tr("LightCraft Preset"), &["lcpreset"])
                .set_file_name(name)
                .save_file()
                .map(|p| p.to_string_lossy().to_string())
        })),
        pick_curve_preset_files: Some(Box::new(|| {
            rfd::FileDialog::new()
-                .set_title("Import Point Curve Presets")
-                .add_filter("Point Curve Presets", &["lccurve", "json"])
+                .set_title(lightcraft_ui_egui::i18n::tr("Import Point Curve Presets"))
+                .add_filter_nocase(lightcraft_ui_egui::i18n::tr("Point Curve Presets"), &["lccurve", "json"])
                .pick_files()
                .unwrap_or_default()
                .into_iter()
@@ -304,8 +392,8 @@ fn services() -> Services {
        })),
        save_curve_preset_file: Some(Box::new(|name: &str| {
            rfd::FileDialog::new()
-                .set_title("Export Point Curve Presets")
-                .add_filter("Point Curve Presets", &["lccurve"])
+                .set_title(lightcraft_ui_egui::i18n::tr("Export Point Curve Presets"))
+                .add_filter_nocase(lightcraft_ui_egui::i18n::tr("Point Curve Presets"), &["lccurve"])
                .set_file_name(name)
                .save_file()
                .map(|p| p.to_string_lossy().to_string())
@@ -316,6 +404,9 @@ fn services() -> Services {
        png: Some(Box::new(|img: &lightcraft_raster::Rgba8| {
            lightcraft_codecs::encode_png(&lightcraft_codecs::EncodeImage::rgba8(img), &lightcraft_codecs::EncodeMeta::default()).unwrap_or_default()
        })),
+        // the library is a folder on disk: backed up with the user's other files
+        backup_library: None,
+        restore_library: None,
    }
 }

@@ -330,7 +421,7 @@ fn open_session(in_memory: bool, dir: Option<std::path::PathBuf>, seed_demo: boo
    }
    let unopened = || Session::new().with_fs().with_system_clock();
    let Some(dir) = dir else {
-        eprintln!("lightcraft: no library location (set --library or LIGHTCRAFT_LIBRARY)");
+        log::warn!("no library location (set --library or LIGHTCRAFT_LIBRARY)");
        return (unopened(), Some(LibraryProblem::new("", "There is no home folder to keep the library in. Choose a folder for it.")));
    };
    let t0 = std::time::Instant::now();
@@ -338,8 +429,8 @@ fn open_session(in_memory: bool, dir: Option<std::path::PathBuf>, seed_demo: boo
    match s.open_library(&dir, seed_demo) {
        Ok(r) => {
            let (replayed, torn) = (r.replayed, r.torn_bytes);
-            eprintln!(
-                "lightcraft: library {}: {} photos, {replayed} log records replayed{} ({:.1} ms)",
+            log::info!(
+                "library {}: {} photos, {replayed} log records replayed{} ({:.1} ms)",
                dir.display(),
                s.catalog.len(),
                if torn > 0 { ", torn tail repaired" } else { "" },
@@ -348,7 +439,7 @@ fn open_session(in_memory: bool, dir: Option<std::path::PathBuf>, seed_demo: boo
            (s, None)
        }
        Err(e) => {
-            eprintln!("lightcraft: can't open library {}: {e}", dir.display());
+            log::error!("can't open library {}: {e}", dir.display());
            (unopened(), Some(LibraryProblem::new(dir.to_string_lossy(), e.to_string())))
        }
    }
@@ -366,12 +457,72 @@ OPTIONS:
  --control PORT   serve the JSON-lines control channel on 127.0.0.1:PORT (env LIGHTCRAFT_CONTROL_PORT;
                   see docs/control-protocol.md)
  --version, --help
+
+ENVIRONMENT:
+  LIGHTCRAFT_GPU_BACKEND=dx12|vulkan|metal|auto|off   graphics backend (default: DX12 on Windows, Metal on macOS,
+                   Vulkan on Linux; off = render on the CPU); else WGPU_BACKEND. LIGHTCRAFT_GPU=0: CPU rendering.
+  LIGHTCRAFT_SAM3_DIR=DIR   the SAM 3 model for Object / Describe masks (default: <settings folder>/models/sam3;
+                   optional: LightCraft offers to download it when first needed)
+  LIGHTCRAFT_SAM3_MIRRORS=URL,…   where to download the SAM 3 model from (base URLs, tried in order)
+  LIGHTCRAFT_LOG=info|debug   more log detail from LightCraft itself (default: info from LightCraft, warnings
+                   from other crates); else RUST_LOG=<env_logger directives>. Records go to stderr and to
+                   <settings folder>/logs/lightcraft.log (previous runs: lightcraft.1.log, lightcraft.2.log)
 ";

+/// The launch arguments' files and folders to import (absolute), and a notice for each one that
+/// is not imported (see [`lightcraft_engine::import::launch_path`]; issue #374).
+fn launch_imports(args: &[String]) -> (Vec<String>, Vec<String>) {
+    let cwd = std::env::current_dir().ok();
+    let home = std::env::var_os(if cfg!(windows) { "USERPROFILE" } else { "HOME" }).filter(|h| !h.is_empty()).map(std::path::PathBuf::from);
+    launch_imports_in(args, cwd.as_deref(), home.as_deref())
+}
+
+fn launch_imports_in(args: &[String], cwd: Option<&std::path::Path>, home: Option<&std::path::Path>) -> (Vec<String>, Vec<String>) {
+    use lightcraft_engine::import::{LaunchPath, launch_path};
+    let (mut files, mut notices) = (Vec::new(), Vec::new());
+    for a in args {
+        match launch_path(a, cwd, home, lightcraft_engine::devices::dcim_in) {
+            Some(LaunchPath::Import(p)) => files.push(p),
+            Some(LaunchPath::Refused { path, why }) => {
+                log::warn!("not importing {path} given at launch: {why}");
+                notices
+                    .push(format!("{path} was not imported: it is {why}. To import from it, choose a folder inside it with File ▸ Import Photos…"));
+            }
+            None => {}
+        }
+    }
+    (files, notices)
+}
+
+/// Where the log files live: `logs` in the settings folder, next to `ui.json` (see `logging`).
+/// None with `LIGHTCRAFT_NO_PREFS` (tests, scripts), so those runs don't rotate away the user's logs.
+fn log_dir() -> Option<std::path::PathBuf> {
+    if std::env::var_os("LIGHTCRAFT_NO_PREFS").is_some() {
+        return None;
+    }
+    config_dir().map(|d| d.join("logs"))
+}
+
+/// The control port `value` names; a value that isn't a port is logged and ignored (`what` is
+/// the option or variable it came from). Logged before the log file opens, so it is kept for it.
+fn control_port_from(what: &str, value: Option<String>) -> Option<u16> {
+    let value = value?;
+    let port = value.trim().parse().ok();
+    if port.is_none() {
+        log::warn!("{what} {value:?} is not a port number; no control server");
+    }
+    port
+}
+
 fn main() -> eframe::Result {
+    // First, so every start-up record is kept for the log file (`logging`).
+    let logger = logging::install();
    lightcraft_engine::guard::install_hook(std::env::temp_dir().join("lightcraft-panics.log"));
+    if let Some(logger) = logger {
+        logging::record_panics(logger);
+    }
    alloc_release::install();
-    let mut control_port: Option<u16> = std::env::var("LIGHTCRAFT_CONTROL_PORT").ok().and_then(|p| p.parse().ok());
+    let mut control_port = control_port_from("LIGHTCRAFT_CONTROL_PORT", std::env::var("LIGHTCRAFT_CONTROL_PORT").ok().filter(|v| !v.is_empty()));
    let mut files = Vec::new();
    let mut seed_demo = true;
    let mut in_memory = false;
@@ -379,7 +530,7 @@ fn main() -> eframe::Result {
    let mut args = std::env::args().skip(1);
    while let Some(a) = args.next() {
        match a.as_str() {
-            "--control" => control_port = args.next().and_then(|p| p.parse().ok()),
+            "--control" => control_port = control_port_from("--control", Some(args.next().unwrap_or_default())),
            "--library" => library_dir = args.next().map(std::path::PathBuf::from),
            "--no-demo" => seed_demo = false,
            "--memory" | "--demo" => in_memory = true,
@@ -398,7 +549,31 @@ fn main() -> eframe::Result {
            _ => files.push(a),
        }
    }
-    let (prefs, prefs_warning, keep_prefs_file) = load_prefs();
+    // The log file: opened after the arguments, so `--version`, `--help` and a usage error leave
+    // no file behind. Records logged until now are written to it first.
+    let mut log_file = None;
+    if let Some(logger) = logger {
+        // a --memory session writes nothing (issue #164), a log file included
+        match log_dir().filter(|_| !in_memory) {
+            Some(dir) => match logger.attach_dir(&dir) {
+                Ok(path) => {
+                    log::info!("LightCraft {}, log file {}", env!("CARGO_PKG_VERSION"), path.display());
+                    log_file = Some(path);
+                }
+                // The file sink has given up by now, so this goes to standard error only.
+                Err(e) => log::warn!("no log file: {e}"),
+            },
+            None => logger.no_file(),
+        }
+    }
+    // what the arguments name, resolved now: an empty or relative argument never becomes a drive
+    // root, and a whole drive or home folder is not walked (issue #374)
+    let (files, launch_notices) = launch_imports(&files);
+    let (prefs, prefs_warning, keep_prefs_file) = load_prefs(in_memory);
+    // the saved language from the start, so a failed start is reported in it too
+    if let Some(ui) = &prefs {
+        lightcraft_ui_egui::i18n::set_language(ui.language);
+    }
    // --library, else the library last opened from Settings, else the default location
    let library_dir = library_dir.or_else(|| {
        prefs
@@ -408,6 +583,11 @@ fn main() -> eframe::Result {
            .map(Into::into)
    });
    let library_dir = library_dir.or_else(lightcraft_engine::library::default_dir);
+    // GPU compute: off if the preference says so, or if the last launch died creating the device
+    // (issue #136) — before anything can create it
+    let gpu_crash = gpu_crash_check(in_memory);
+    let gpu_on = prefs.as_ref().is_none_or(|u| u.settings.gpu) && gpu_crash.is_none();
+    lightcraft_engine::gpu::set_enabled(gpu_on);
    let options = eframe::NativeOptions {
        viewport: egui::ViewportBuilder::default()
            .with_title("LightCraft")
@@ -420,26 +600,41 @@ fn main() -> eframe::Result {
            .with_icon(app_icon())
            // Wayland matches the window to packaging/linux/ai.storyteller.lightcraft.desktop by this id
            .with_app_id(APP_ID),
+        wgpu_options: window_wgpu_options(),
        ..Default::default()
    };
-    eframe::run_native(
+    let started = eframe::run_native(
        "LightCraft",
        options,
        Box::new(move |cc| {
-            let (session, problem) = open_session(in_memory, library_dir, seed_demo && files.is_empty());
+            let (mut session, problem) = open_session(in_memory, library_dir, seed_demo && files.is_empty());
+            // AI masks: the SAM 3 checkpoint (facebook/sam3) in <config>/models/sam3, or LIGHTCRAFT_SAM3_DIR
+            // (never required: without it, AI masks offer to download it; see docs/ai-masks.md)
+            session.segmenter.dir =
+                std::env::var_os("LIGHTCRAFT_SAM3_DIR").map(std::path::PathBuf::from).or_else(|| config_dir().map(|d| d.join("models").join("sam3")));
+            // the user's own download locations, one base URL per line (LIGHTCRAFT_SAM3_MIRRORS too)
+            session.segmenter.mirrors_file = config_dir().map(|d| d.join("models").join("sam3-mirrors.txt"));
            let mut app = LightcraftApp::new(session, services());
            if let Some(ui) = prefs {
                app.ui = ui;
            }
+            lightcraft_ui_egui::i18n::set_language(app.ui.language);
            app.integrated_titlebar = cfg!(target_os = "macos");
            app.notices.extend(prefs_warning);
+            app.notices.extend(launch_notices);
            // what's on disk now: only changes are written
            let writer = PrefsWriter {
+                path: if in_memory { None } else { prefs_path() },
                written: serde_json::to_vec_pretty(&app.ui).unwrap_or_default(),
                library: app.ui.settings.library_path.clone(),
                keep_file: keep_prefs_file,
                ..Default::default()
            };
+            // after the snapshot above, so the writer saves the switched-off preference
+            if let Some(notice) = gpu_crash {
+                app.ui.settings.gpu = false;
+                app.notices.push(notice);
+            }
            if let Some(port) = control_port {
                let rx = control_server::start(port, cc.egui_ctx.clone());
                app = app.with_control(rx);
@@ -449,7 +644,12 @@ fn main() -> eframe::Result {
                p.pending_import = files;
                app.library_problem = Some(p);
            } else if !files.is_empty() {
-                let _ = app.run("library.import", serde_json::json!({"paths": files}));
+                // listed and read on the import worker once the window shows (issue #374: never
+                // here, before the first frame, where a large folder kept the window from
+                // appearing)
+                if let Err(e) = lightcraft_ui_egui::import::start_paths(&mut app, files) {
+                    log::warn!("import at launch: {e}");
+                }
                app.ui.view = lightcraft_ui_egui::state::ViewMode::PhotoGrid;
            }
            // native menu bar generated from the command registry (macOS; elsewhere the menus are
@@ -463,7 +663,28 @@ fn main() -> eframe::Result {
                menu,
            )))
        }),
-    )
+    );
+    if let Err(e) = &started {
+        startup_failed(&e.to_string(), log_file.as_deref());
+    }
+    started
+}
+
+/// The window could not start (e.g. no usable graphics device): say so in the log and in a native
+/// message box naming the log file, instead of exiting without a trace — the release builds have
+/// no console on Windows, and an app started from Finder shows no standard error (issue #260).
+fn startup_failed(error: &str, log_file: Option<&std::path::Path>) {
+    log::error!("LightCraft could not open its window: {error}");
+    if std::env::var_os("LIGHTCRAFT_NO_PREFS").is_some() {
+        return; // tests and scripts: no dialog to click away
+    }
+    let (title, text) = lightcraft_ui_egui::i18n::startup_failed_message(error, log_file.map(|p| p.display().to_string()).as_deref());
+    let _ = rfd::MessageDialog::new()
+        .set_level(rfd::MessageLevel::Error)
+        .set_title(title)
+        .set_description(text)
+        .set_buttons(rfd::MessageButtons::Ok)
+        .show();
 }

 #[cfg(test)]
@@ -478,6 +699,24 @@ mod tests {
        d
    }

+    /// Issue #374: launch arguments that would walk a whole drive or home folder are reported,
+    /// not imported; empty ones are ignored; the rest are imported as absolute paths.
+    #[test]
+    fn launch_arguments_never_walk_a_drive_or_the_home_folder() {
+        let home = dir("launch");
+        std::fs::create_dir_all(home.join("Trip")).unwrap();
+        let args: Vec<String> = ["", "  ", ".", "Trip", &home.to_string_lossy()].iter().map(|s| s.to_string()).collect();
+        let (files, notices) = launch_imports_in(&args, Some(&home), Some(&home));
+        assert_eq!(files, [home.join("Trip").to_string_lossy().to_string()]);
+        assert_eq!(notices.len(), 2, "{notices:?}");
+        assert!(notices.iter().all(|n| n.contains("was not imported")), "{notices:?}");
+        // the working folder is a drive root (a launcher's choice): `.` is never the whole drive
+        let root = home.ancestors().last().unwrap().to_path_buf();
+        let (files, notices) = launch_imports_in(&[".".to_string()], Some(&root), None);
+        assert!(files.iter().all(|f| f.ends_with("DCIM")) && files.len() + notices.len() == 1, "{files:?} {notices:?}");
+        let _ = std::fs::remove_dir_all(&home);
+    }
+
    /// Issue #103: a damaged ui.json (which holds the library location) is kept aside and
    /// reported, not silently replaced by the defaults.
    #[test]
@@ -485,7 +724,7 @@ mod tests {
        let d = dir("damaged");
        let path = d.join("ui.json");
        std::fs::write(&path, br#"{"settings": {"library_path": "/Volumes/Photos/Lib"#).unwrap();
-        let (ui, warning, keep) = load_prefs_at(&path);
+        let (ui, warning, keep) = load_prefs_at(&path, true);
        assert!(ui.is_none() && !keep);
        let warning = warning.unwrap();
        assert!(warning.contains("damaged") && warning.contains("ui.json.corrupt-"), "{warning}");
@@ -493,10 +732,133 @@ mod tests {
        let kept: Vec<_> = std::fs::read_dir(&d).unwrap().map(|e| e.unwrap().file_name().to_string_lossy().to_string()).collect();
        assert!(kept.len() == 1 && kept[0].starts_with("ui.json.corrupt-"), "{kept:?}");
        // a missing file is just "no settings yet"
-        assert_eq!(load_prefs_at(&path).1, None);
+        assert_eq!(load_prefs_at(&path, true).1, None);
        let _ = std::fs::remove_dir_all(&d);
    }

+    /// Issue #164: a `--memory` session reads the settings but writes nothing — a damaged file is
+    /// reported and left where it is, not set aside.
+    #[test]
+    fn memory_session_leaves_a_damaged_ui_json_alone() {
+        let d = dir("damaged-memory");
+        let path = d.join("ui.json");
+        let bytes = br#"{"settings": {"library_path": "/Volumes/Photos/Lib"#;
+        std::fs::write(&path, bytes).unwrap();
+        let (ui, warning, keep) = load_prefs_at(&path, false);
+        assert!(ui.is_none() && keep);
+        let warning = warning.unwrap();
+        assert!(warning.contains("damaged") && warning.contains("nothing is saved"), "{warning}");
+        assert_eq!(std::fs::read(&path).unwrap(), bytes);
+        assert_eq!(std::fs::read_dir(&d).unwrap().count(), 1);
+        let _ = std::fs::remove_dir_all(&d);
+    }
+
+    /// Issue #164: the writer saves changed settings to its file — and nothing at all without one
+    /// (`--memory`) or while the session is the temporary one offered when the library can't open.
+    #[test]
+    fn prefs_writer_writes_nothing_in_a_memory_or_temporary_session() {
+        let d = dir("writer");
+        let path = d.join("sub").join("ui.json");
+        let mut ui = UiState::default();
+        // an ordinary session: a change is written, the folder created on the way
+        let mut w = PrefsWriter { path: Some(path.clone()), ..Default::default() };
+        ui.thumb_size += 50.0;
+        w.save_ui(&ui, false).unwrap();
+        let saved = std::fs::read(&path).unwrap();
+        assert!(String::from_utf8_lossy(&saved).contains("thumbSize"), "{}", String::from_utf8_lossy(&saved));
+        // the temporary session (library problem): a further change is not written…
+        ui.thumb_size += 50.0;
+        w.save_ui(&ui, true).unwrap();
+        assert_eq!(std::fs::read(&path).unwrap(), saved);
+        // …until a library opens
+        w.save_ui(&ui, false).unwrap();
+        assert_ne!(std::fs::read(&path).unwrap(), saved);
+        // --memory: no path, so no file and no folder, whatever changes
+        let d2 = dir("writer-memory");
+        let _ = std::fs::remove_dir_all(&d2);
+        let mut w = PrefsWriter { path: None, ..Default::default() };
+        ui.thumb_size += 50.0;
+        w.save_ui(&ui, false).unwrap();
+        assert!(w.written.is_empty() && !d2.exists());
+        let _ = std::fs::remove_dir_all(&d);
+    }
+
+    /// Issue #169: a `--memory` session neither arms the GPU crash sentinel (which would create
+    /// the settings folder) nor removes a marker a crashed launch left; it still reports it, and
+    /// the next ordinary launch finds it, reports it and clears it.
+    #[test]
+    fn memory_session_leaves_the_gpu_marker_and_folder_alone() {
+        let d = dir("gpu-marker-memory");
+        let _ = std::fs::remove_dir_all(&d);
+        let m = d.join("gpu-init.marker");
+        // nothing left behind: no notice, and the folder is not created
+        assert_eq!(gpu_crash_check_at(Some(m.clone()), true), None);
+        assert!(!d.exists(), "a --memory session must not create the settings folder");
+        // a marker left by a crashed launch: reported, kept
+        std::fs::create_dir_all(&d).unwrap();
+        std::fs::write(&m, "GPU device creation started (backends METAL)").unwrap();
+        let notice = gpu_crash_check_at(Some(m.clone()), true).unwrap();
+        assert!(notice.contains("GPU rendering is now off"), "{notice}");
+        assert!(m.exists(), "the marker stays for the next ordinary launch");
+        // the next ordinary launch reports it once and removes it
+        assert!(gpu_crash_check_at(Some(m.clone()), false).is_some());
+        lightcraft_engine::gpu::backend::set_init_marker(None);
+        assert!(!m.exists());
+        assert_eq!(gpu_crash_check_at(Some(m.clone()), false), None);
+        lightcraft_engine::gpu::backend::set_init_marker(None);
+        let _ = std::fs::remove_dir_all(&d);
+    }
+
+    /// Issue #136: a GPU init marker left by a crashed launch is reported once and removed.
+    #[test]
+    fn gpu_crash_marker_is_reported_once() {
+        let d = dir("gpu-marker");
+        let m = d.join("gpu-init.marker");
+        assert_eq!(lightcraft_engine::gpu::backend::take_init_marker(&m), None);
+        std::fs::write(&m, "GPU device creation started (backends VULKAN | DX12)").unwrap();
+        let what = lightcraft_engine::gpu::backend::take_init_marker(&m).unwrap();
+        let notice = gpu_crash_notice(&what);
+        assert!(notice.contains("GPU rendering is now off") && notice.contains("Use the GPU for rendering"), "{notice}");
+        assert!(!m.exists());
+        let _ = std::fs::remove_dir_all(&d);
+    }
+
+    /// Issue #136: Windows windows render with DX12 alone (no Vulkan driver loaded) by default.
+    #[test]
+    fn window_backends_follow_the_platform_default() {
+        let eframe::egui_wgpu::WgpuSetup::CreateNew(n) = window_wgpu_options().wgpu_setup else { panic!("expected CreateNew") };
+        let b = n.instance_descriptor.backends;
+        if std::env::var_os("LIGHTCRAFT_GPU_BACKEND").is_none() && std::env::var_os("WGPU_BACKEND").is_none() {
+            if cfg!(windows) {
+                assert_eq!(b, eframe::wgpu::Backends::DX12);
+            } else if cfg!(target_os = "macos") {
+                assert_eq!(b, eframe::wgpu::Backends::METAL);
+            }
+        }
+        assert!(!b.is_empty());
+    }
+
+    /// Issue #234: Windows opens links with the URL protocol handler (the default browser), not
+    /// File Explorer, and passes the whole map link, `?`, `&` and `#` included, as one argument.
+    #[test]
+    fn windows_links_open_in_the_browser() {
+        let url = "https://www.openstreetmap.org/?mlat=48.856600&mlon=2.352200#map=15/48.856600/2.352200";
+        let c = windows_open_url_command(url);
+        assert_eq!(c.get_program(), "rundll32");
+        let args: Vec<&std::ffi::OsStr> = c.get_args().collect();
+        assert_eq!(args, ["url.dll,FileProtocolHandler", url]);
+    }
+
+    #[test]
+    fn a_control_port_that_is_not_a_number_is_ignored() {
+        assert_eq!(control_port_from("--control", Some("7980".into())), Some(7980));
+        assert_eq!(control_port_from("--control", Some(" 18001 ".into())), Some(18001));
+        assert_eq!(control_port_from("--control", Some("nope".into())), None);
+        assert_eq!(control_port_from("--control", Some(String::new())), None);
+        assert_eq!(control_port_from("--control", Some("70000".into())), None);
+        assert_eq!(control_port_from("LIGHTCRAFT_CONTROL_PORT", None), None);
+    }
+
    #[test]
    fn ui_json_is_written_atomically() {
        let d = dir("atomic");
@@ -511,7 +873,7 @@ mod tests {
        assert_eq!(std::fs::read(&path).unwrap(), b"{\"new\": true}");
        let ui = UiState::default();
        write_atomic(&path, &serde_json::to_vec_pretty(&ui).unwrap()).unwrap();
-        let (loaded, warning, _) = load_prefs_at(&path);
+        let (loaded, warning, _) = load_prefs_at(&path, true);
        assert!(loaded.is_some() && warning.is_none());
        let _ = std::fs::remove_dir_all(&d);
    }
@@ -2,9 +2,12 @@
 //! the in-window menus ([`lightcraft_ui_egui::menubar`]): the registry's menu paths, shortcuts,
 //! enabled and checked state, and live labels ("Undo Exposure").
 //!
-//! Key handling: a native key equivalent consumes the key press before egui sees it, so
-//! - shortcuts installed natively are listed in `LightcraftApp::native_shortcuts` and skipped by
-//!   the egui shortcut handler (nothing fires twice);
+//! Key handling: AppKit offers a key press to the menu bar only when it carries ⌘ or ⌃, or is a
+//! function key (F1…). Every other key (`E`, `1`, `⇧P`, `⌥Y`…) goes straight to the window, whose
+//! winit view always takes it, so a menu item never fires from it. Hence
+//! - shortcuts the menu bar really receives ([`menu_delivers`]) are listed in
+//!   `LightcraftApp::native_shortcuts` and skipped by the egui shortcut handler (nothing fires
+//!   twice); the others stay on their menu items for display and egui runs them;
 //! - while a text field has keyboard focus, accelerators without ⌘ (`G`, `1`, `Delete`…) and the
 //!   text-editing ones (⌘A/⌘C/⌘V/⌘X/⌘Z) are removed, so typing and text editing work; they come
 //!   back when the field loses focus.
@@ -51,6 +54,9 @@ pub struct NativeMenu {
    /// Structure of the installed menu (ids, kinds, submenu names); a change rebuilds it.
    structure: String,
    text_focus: bool,
+    /// The keyboard shortcuts editor is recording a key: every accelerator is off so the key
+    /// press reaches it.
+    capturing: bool,
 }

 /// `Cmd+Shift+Z` → a muda accelerator (`None` for keys we leave to egui, e.g. Escape).
@@ -146,9 +152,21 @@ fn yields_to_text(sc: &str) -> bool {
    !sc.contains("Cmd") && !sc.contains("Ctrl") || TEXT_EDIT.contains(&sc)
 }

+/// Whether AppKit hands this shortcut to the menu bar: only key presses with ⌘ or ⌃, and function
+/// keys. A plain `C` or `⇧P` never reaches it (the window's view takes the key), so egui has to run
+/// those even though their menu item shows the key.
+fn menu_delivers(sc: &str) -> bool {
+    sc.split('+').any(|part| matches!(part, "Cmd" | "Ctrl") || part.strip_prefix('F').is_some_and(|n| n.parse::<u8>().is_ok()))
+}
+
+/// The shortcuts the menu bar runs itself, for `LightcraftApp::native_shortcuts`.
+fn owned_by_menu<'a>(installed: impl Iterator<Item = &'a str>, text_focus: bool) -> HashSet<String> {
+    installed.filter(|sc| menu_delivers(sc) && !(text_focus && yields_to_text(sc))).map(str::to_string).collect()
+}
+
 /// `&` marks a mnemonic in muda labels.
 fn label_text(s: &str) -> String {
-    s.replace('&', "&&")
+    lightcraft_ui_egui::i18n::tr(s).replace('&', "&&")
 }

 fn structure_of(bar: &[(String, Vec<MenuNode>)]) -> String {
@@ -171,7 +189,7 @@ fn structure_of(bar: &[(String, Vec<MenuNode>)]) -> String {
            out.push(';');
        }
    }
-    let mut s = String::new();
+    let mut s = format!("{};", lightcraft_ui_egui::i18n::language().code());
    for (t, items) in bar {
        s.push_str(t);
        walk(items, &mut s);
@@ -196,7 +214,7 @@ impl NativeMenu {
            let _ = tx.send(e.id.0);
            repaint.request_repaint();
        }));
-        let mut m = NativeMenu { menu: Menu::new(), items: HashMap::new(), rx, structure: String::new(), text_focus: false };
+        let mut m = NativeMenu { menu: Menu::new(), items: HashMap::new(), rx, structure: String::new(), text_focus: false, capturing: false };
        m.rebuild(app);
        app.native_menu = true;
        m
@@ -210,30 +228,30 @@ impl NativeMenu {

        // the application menu
        let app_menu = Submenu::new("LightCraft", true);
-        let about = MenuItem::with_id("app.about", "About LightCraft", true, None);
-        let settings = MenuItem::with_id(SETTINGS, app.ui.language.tr("Settings…"), true, accelerator(SETTINGS_KEY));
-        let quit = MenuItem::with_id(QUIT, "Quit LightCraft", true, accelerator("Cmd+Q"));
+        let about = MenuItem::with_id("app.about", lightcraft_ui_egui::i18n::tr("About LightCraft"), true, None);
+        let settings = MenuItem::with_id(SETTINGS, lightcraft_ui_egui::i18n::tr("Settings…"), true, accelerator(SETTINGS_KEY));
+        let quit = MenuItem::with_id(QUIT, lightcraft_ui_egui::i18n::tr("Quit LightCraft"), true, accelerator("Cmd+Q"));
        let _ = app_menu.append_items(&[
            &about,
            &PredefinedMenuItem::separator(),
            &settings,
            &PredefinedMenuItem::separator(),
-            &PredefinedMenuItem::services(None),
+            &PredefinedMenuItem::services(Some(lightcraft_ui_egui::i18n::tr("Services"))),
            &PredefinedMenuItem::separator(),
-            &PredefinedMenuItem::hide(Some("Hide LightCraft")),
-            &PredefinedMenuItem::hide_others(None),
-            &PredefinedMenuItem::show_all(None),
+            &PredefinedMenuItem::hide(Some(lightcraft_ui_egui::i18n::tr("Hide LightCraft"))),
+            &PredefinedMenuItem::hide_others(Some(lightcraft_ui_egui::i18n::tr("Hide Others"))),
+            &PredefinedMenuItem::show_all(Some(lightcraft_ui_egui::i18n::tr("Show All"))),
            &PredefinedMenuItem::separator(),
            &quit,
        ]);
        let _ = self.menu.append(&app_menu);

        for (title, nodes) in &bar {
-            let sub = Submenu::new(title, true);
-            if title == app.ui.language.tr("Window") {
+            let sub = Submenu::new(label_text(title), true);
+            if title == "Window" {
                let _ = sub.append_items(&[
-                    &PredefinedMenuItem::minimize(None),
-                    &PredefinedMenuItem::maximize(Some("Zoom")),
+                    &PredefinedMenuItem::minimize(Some(lightcraft_ui_egui::i18n::tr("Minimize"))),
+                    &PredefinedMenuItem::maximize(Some(lightcraft_ui_egui::i18n::tr("Zoom"))),
                    &PredefinedMenuItem::separator(),
                ]);
            }
@@ -245,21 +263,28 @@ impl NativeMenu {
                .collect();
            let nodes = tidy_separators(nodes);
            self.append_nodes(&sub, &nodes);
-            if title == app.ui.language.tr("File") {
+            if title == "File" {
                // ⌘W, the system's own item
-                let _ = sub.append_items(&[&PredefinedMenuItem::separator(), &PredefinedMenuItem::close_window(None)]);
+                let _ = sub.append_items(&[
+                    &PredefinedMenuItem::separator(),
+                    &PredefinedMenuItem::close_window(Some(lightcraft_ui_egui::i18n::tr("Close Window"))),
+                ]);
            }
-            if title == app.ui.language.tr("Window") {
-                let _ = sub.append_items(&[&PredefinedMenuItem::separator(), &PredefinedMenuItem::bring_all_to_front(None)]);
+            if title == "Window" {
+                let _ = sub.append_items(&[
+                    &PredefinedMenuItem::separator(),
+                    &PredefinedMenuItem::bring_all_to_front(Some(lightcraft_ui_egui::i18n::tr("Bring All to Front"))),
+                ]);
                sub.set_as_windows_menu_for_nsapp();
            }
-            if title == app.ui.language.tr("Help") {
+            if title == "Help" {
                sub.set_as_help_menu_for_nsapp();
            }
            let _ = self.menu.append(&sub);
        }
        self.menu.init_for_nsapp();
        self.text_focus = false;
+        self.capturing = false;
        self.publish_shortcuts(app);
    }

@@ -282,12 +307,23 @@ impl NativeMenu {
                    let accel = shortcut.as_deref().filter(|s| !CONTEXTUAL.contains(s)).and_then(accelerator);
                    let handle = match checked {
                        Some(c) => {
-                            let it = CheckMenuItem::with_id(key.clone(), label_text(label), *enabled, *c, accel);
+                            let it = CheckMenuItem::with_id(
+                                key.clone(),
+                                lightcraft_ui_egui::menubar::display_item_label(id, params, label).replace('&', "&&"),
+                                *enabled,
+                                *c,
+                                accel,
+                            );
                            let _ = sub.append(&it);
                            Handle::Check(it)
                        }
                        None => {
-                            let it = MenuItem::with_id(key.clone(), label_text(label), *enabled, accel);
+                            let it = MenuItem::with_id(
+                                key.clone(),
+                                lightcraft_ui_egui::menubar::display_item_label(id, params, label).replace('&', "&&"),
+                                *enabled,
+                                accel,
+                            );
                            let _ = sub.append(&it);
                            Handle::Plain(it)
                        }
@@ -312,19 +348,16 @@ impl NativeMenu {

    /// Tell the egui shortcut handler which shortcuts the menu bar currently owns.
    fn publish_shortcuts(&self, app: &mut LightcraftApp) {
-        app.native_shortcuts = self
-            .items
-            .values()
-            .filter(|i| i.accel.is_some())
-            .filter_map(|i| i.shortcut.clone())
-            .filter(|sc| !(self.text_focus && yields_to_text(sc)))
-            .collect::<HashSet<_>>();
+        let installed = self.items.values().filter(|i| i.accel.is_some()).filter_map(|i| i.shortcut.as_deref());
+        // (none while the keymap editor records a shortcut: every key goes to it)
+        app.native_shortcuts = if self.capturing { HashSet::new() } else { owned_by_menu(installed, self.text_focus) };
        app.native_shortcuts.insert(SETTINGS_KEY.to_string());
    }

    /// Per frame: run chosen items, then sync labels / enabled / checked and the text-focus
    /// accelerators with the app state.
    pub fn update(&mut self, app: &mut LightcraftApp, ctx: &egui::Context) {
+        lightcraft_ui_egui::i18n::set_language(app.ui.language);
        while let Ok(key) = self.rx.try_recv() {
            if key == QUIT {
                ctx.send_viewport_cmd(egui::ViewportCommand::Close);
@@ -352,8 +385,8 @@ impl NativeMenu {
                        let Some(it) = items.get_mut(&MenuNode::key(id, params)) else { continue };
                        if it.label != *label {
                            match &it.handle {
-                                Handle::Plain(h) => h.set_text(label_text(label)),
-                                Handle::Check(h) => h.set_text(label_text(label)),
+                                Handle::Plain(h) => h.set_text(lightcraft_ui_egui::menubar::display_item_label(id, params, label).replace('&', "&&")),
+                                Handle::Check(h) => h.set_text(lightcraft_ui_egui::menubar::display_item_label(id, params, label).replace('&', "&&")),
                            }
                            it.label = label.clone();
                        }
@@ -379,14 +412,16 @@ impl NativeMenu {
        walk(&bar.iter().flat_map(|(_, v)| v.clone()).collect::<Vec<_>>(), &mut self.items);

        let focus = ctx.egui_wants_keyboard_input();
-        if focus != self.text_focus {
+        let capturing = app.recording_shortcut.is_some();
+        if focus != self.text_focus || capturing != self.capturing {
            self.text_focus = focus;
+            self.capturing = capturing;
            for it in self.items.values() {
                let Some(sc) = it.shortcut.as_deref() else { continue };
-                if it.accel.is_none() || !yields_to_text(sc) {
+                if it.accel.is_none() {
                    continue;
                }
-                let accel = if focus { None } else { it.accel };
+                let accel = if capturing || (focus && yields_to_text(sc)) { None } else { it.accel };
                let _ = match &it.handle {
                    Handle::Plain(h) => h.set_accelerator(accel),
                    Handle::Check(h) => h.set_accelerator(accel),
@@ -401,6 +436,27 @@ impl NativeMenu {
 mod tests {
    use super::*;

+    /// The menu model's titles stay English, so only the language can tell the native menu to
+    /// rebuild its titles (and the macOS app menu): every language switch — also between two CJK
+    /// languages — must change the structure key.
+    #[test]
+    fn switching_language_rebuilds_native_menu_structure() {
+        use lightcraft_ui_egui::i18n::{Locale, set_language};
+        let app = LightcraftApp::new(lightcraft_engine::Session::with_demo(), Default::default());
+        set_language(Locale::En);
+        let bar = menu_bar(&app);
+        let mut seen = std::collections::BTreeSet::new();
+        for language in Locale::ALL {
+            set_language(*language);
+            assert!(seen.insert(structure_of(&bar)), "{language:?} shares another language's menu structure key");
+        }
+        set_language(Locale::ZhHant);
+        assert_eq!(label_text("File"), "檔案");
+        assert_eq!(label_text("Settings…"), "設定…");
+        assert_eq!(label_text("Quit LightCraft"), "結束 LightCraft");
+        set_language(Locale::En);
+    }
+
    #[test]
    fn shortcuts_map_to_accelerators() {
        assert_eq!(accelerator("Cmd+Shift+Z"), Some(Accelerator::new(Modifiers::META | Modifiers::SHIFT, Code::KeyZ)));
@@ -428,4 +484,39 @@ mod tests {
            assert!(accelerator(sc).is_some(), "{sc}");
        }
    }
+
+    /// Single keys shown in the menu bar (E, C, ⇧P, ratings…) never reach it on macOS, so egui must
+    /// keep handling them; ⌘ / ⌃ combinations and function keys are the menu bar's own.
+    #[test]
+    fn single_key_shortcuts_stay_with_egui() {
+        assert!(menu_delivers("Cmd+Shift+H") && menu_delivers("Ctrl+H") && menu_delivers("F2") && menu_delivers("Cmd+F11"));
+        assert!(!menu_delivers("E") && !menu_delivers("Shift+P") && !menu_delivers("Alt+Y") && !menu_delivers("1") && !menu_delivers("F"));
+        let app = LightcraftApp::new(lightcraft_engine::Session::with_demo(), Default::default());
+        fn all(n: &[MenuNode], out: &mut Vec<String>) {
+            for x in n {
+                match x {
+                    MenuNode::Item { shortcut: Some(s), .. } if accelerator(s).is_some() => out.push(s.clone()),
+                    MenuNode::Submenu { children, .. } => all(children, out),
+                    _ => {}
+                }
+            }
+        }
+        let mut installed = Vec::new();
+        for (_, v) in menu_bar(&app) {
+            all(&v, &mut installed);
+        }
+        for sc in ["E", "C", "Shift+P", "Cmd+Shift+H", "F2"] {
+            assert!(installed.iter().any(|s| s == sc), "{sc} is in the menu bar");
+        }
+        let owned = owned_by_menu(installed.iter().map(String::as_str), false);
+        for sc in ["E", "C", "Shift+P", "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "P", "U"] {
+            assert!(installed.iter().any(|s| s == sc), "{sc} is displayed in the menu");
+            assert!(!owned.contains(sc), "{sc} must be left to egui");
+        }
+        for sc in ["Cmd+Shift+H", "F2"] {
+            assert!(owned.contains(sc), "{sc} is run by the menu bar");
+        }
+        // while typing, the menu bar gives up F2 too (the text field has it)
+        assert!(!owned_by_menu(installed.iter().map(String::as_str), true).contains("F2"));
+    }
 }
@@ -9,9 +9,10 @@ covers a whole directory), or if a licence file referenced in the Licence column
 | Path | Asset | Creator | Source | Licence | Added | Modifications |
 |---|---|---|---|---|---|---|
 | `assets/fonts/Inter-*.ttf` (Regular, Medium, SemiBold) | Inter | Rasmus Andersson | https://github.com/rsms/inter | SIL Open Font License 1.1 (`assets/fonts/OFL-Inter.txt`) | 2026-09-30 | none |
-| `assets/fonts/BIZUDMincho-Regular.ttf` | BIZ UDMincho Regular | The BIZ UDMincho Project Authors (Morisawa Inc., design TypeBank Co., Ltd.) | https://github.com/google/fonts/tree/63833b7d10bb1f86a8f0b91cba2d3ae1f68d1aa3/ofl/bizudmincho | OFL-1.1 (`assets/fonts/OFL-BIZUDMincho.txt`) | 2026-10-05 | none |
-| `assets/fonts/OFL-BIZUDMincho.txt` | BIZ UDMincho licence | The BIZ UDMincho Project Authors | https://github.com/google/fonts/blob/63833b7d10bb1f86a8f0b91cba2d3ae1f68d1aa3/ofl/bizudmincho/OFL.txt | OFL-1.1 | 2026-10-05 | none |
 | `assets/app-icon/` (`lightcraft.svg` and the PNG/ICNS/ICO/SVG files derived from it) | LightCraft app icon (lynx) | LightCraft project owner (drawn in ArtCraft) | original work (vectorised from the owner's drawing; see `assets/app-icon/README.md`) | MIT OR Apache-2.0 (`assets/app-icon/LICENSE.txt`) | 2026-10-02 | vectorised to SVG; rendered to PNG/ICNS/ICO by `packaging/icons.sh` |
+| `assets/camera-profiles/*.json` | Camera colour profiles (matrix + hue/saturation/value table), built into LightCraft | ILCE-7M4: Harald Hoyer | original work: fitted by `lightcraft-cli calibrate` to the contributor's own raw photos and their in-camera JPEGs (597 ILCE-7M4 photos, 2026); aggregate colour statistics only, no image content; no Adobe or third-party profile data | MIT OR Apache-2.0 | 2026-10-07 | none |
+| `packaging/macos/dmg/` (`background.svg`, the `background.tiff` rendered from it by `generate.py`, and the `dmg-layout.DS_Store` layout file) | LightCraft macOS DMG window background | @XusBadia | original work for this repository, derived from the LightCraft app icon (`assets/app-icon/lightcraft.svg`, referenced via `<image>`, not copied); text is outlined Inter / JetBrains Mono glyph paths | MIT OR Apache-2.0 | 2026-10-08 | none (original); used for the Finder window of the macOS DMG, `packaging/macos/dmg/generate.py` renders it to `background.tiff` |
+| `assets/camera-profiles/X-H2S.json`, `assets/camera-profiles/X-T4.json` | Fujifilm camera colour profiles (matrix + hue/saturation/value table), built into LightCraft | LightCraft contributors; source photographs supplied by Sebastian Pfluegelmeier | original work: fitted by `lightcraft-cli calibrate` to 201 X-H2S and 545 X-T4 RAFs and their in-camera JPEGs; aggregate colour statistics only, no image content; no Adobe or third-party profile data | MIT OR Apache-2.0 | 2026-10-08 | none |
 | `crates/scenes/` (generated images) | Procedural demo photographs | LightCraft contributors | original work (generated at runtime, no source imagery) | MIT OR Apache-2.0 | 2026-09-30 | n/a |
 | `crates/ui-egui/src/icons.rs` | UI icons drawn as vector paths in code | LightCraft contributors | original work | MIT OR Apache-2.0 | 2026-09-30 | n/a |
 | `docs/images/*-tetons.jpg`, `docs/images/grid-pd.jpg` (screenshots containing it) | "The Tetons and the Snake River" | Ansel Adams (1942), U.S. National Archives | https://commons.wikimedia.org/wiki/File:Adams_The_Tetons_and_the_Snake_River.jpg | Public domain (U.S. federal government work) | 2026-09-30 | developed in LightCraft; shown inside app screenshots |
@@ -20,7 +21,12 @@ covers a whole directory), or if a licence file referenced in the Licence column
 | `docs/images/*-blue-marble.jpg`, `docs/images/grid-pd.jpg` | "The Blue Marble" (AS17-148-22727) | NASA, Apollo 17 crew (1972) | https://commons.wikimedia.org/wiki/File:The_Earth_seen_from_Apollo_17.jpg | Public domain (NASA) | 2026-09-30 | developed in LightCraft; shown inside app screenshots |
 | `docs/images/*.jpg` (UI) | LightCraft application screenshots | LightCraft contributors | original work (captured with `docs/showcase/`) | MIT OR Apache-2.0 | 2026-09-30 | n/a |
 | `docs/brand/` (artcraft-logo and artcraft-mark, SVG and PNG) | ArtCraft wordmark and mark | ArtCraft Team | original work (https://getartcraft.com/) | ArtCraft trademark, see `docs/brand/LICENSE-brand.txt` (not open source) | 2026-10-01 | none |
+| craft-fonts: optional build input, not files in this repository | BIZ UDPGothic (Regular, Bold), BIZ UDMincho Regular, Shippori Mincho Regular | Morisawa Inc. / The BIZ UDGothic and BIZ UDMincho Project Authors; The Shippori Mincho Project Authors (per craft-fonts' attribution) | https://github.com/storytold/craft-fonts/blob/main/ATTRIBUTION.md | SIL Open Font License 1.1 (each font's OFL.txt in craft-fonts; release packages ship it as OFL-<family>.txt) | 2026-10-06 | none; embedded only in builds made with `CRAFT_FONTS_DIR` (all official releases); the web (wasm32) build embeds BIZ UDPGothic Regular only |

 Notes
 - Fonts authored or published by Adobe (Source Sans/Serif/Code, Source Han, …) are not used, even though some are
  OFL-licensed: the asset rule excludes anything from Adobe. Source Sans 3 was removed on 2026-09-30 and replaced by Inter.
+- Japanese fonts (BIZ UDPGothic, BIZ UDMincho, Shippori Mincho) are not in this repository. They live in
+  [storytold/craft-fonts](https://github.com/storytold/craft-fonts), with their licences and attribution in its
+  `ATTRIBUTION.md`, and are embedded only in builds made with the optional `CRAFT_FONTS_DIR` build input (all official
+  releases). Never commit font files here; add new fonts to craft-fonts (craftrules `standards/fonts.md`).
@@ -0,0 +1 @@
+{"version":1,"model":"ILCE-7M4","files":597,"samples":2182876,"matrix":[[1.06975,-0.0709886,-0.000770444],[-0.0169822,1.08012,-0.0651276],[-0.114835,-0.601525,1.74804]],"hue_sat":{"hue_divisions":72,"sat_divisions":5,"val_divisions":5,"data":[[0.0,1.0,1.0],[-0.819008,1.14375,1.0],[-6.07446,1.10974,1.0],[-4.0478,1.04285,1.0],[-0.546764,1.00329,1.0],[0.0,1.0,1.0],[-1.0412,1.10597,1.0],[-7.22645,1.05878,1.0],[-7.30635,0.989387,1.0],[-5.18589,0.974522,1.0],[0.0,1.0,1.0],[-1.02364,1.06303,1.0],[-6.94669,1.01579,1.0],[-7.47614,0.955435,1.0],[-7.02579,0.940854,1.0],[0.0,1.0,1.0],[-0.29852,1.04349,1.0],[-6.37202,1.00021,1.0],[-7.52098,0.935457,1.0],[-7.45702,0.922239,1.0],[0.0,1.0,1.0],[0.367464,1.03266,1.0],[-4.96951,0.996822,1.0],[-7.41706,0.948709,1.0],[-8.04735,0.91672,1.0],[0.0,1.0,1.0],[0.0388419,1.02587,1.0],[-4.47266,1.01282,1.0],[-7.26834,0.987279,1.0],[-9.02713,0.921453,1.0],[0.0,1.0,1.0],[-0.297476,1.02333,1.0],[-4.6323,1.00993,1.0],[-8.57248,0.962973,1.0],[-12.2375,0.872088,1.0],[0.0,1.0,1.0],[-0.785867,1.02786,1.0],[-4.73124,1.00876,1.0],[-9.09856,0.955343,1.0],[-12.4324,0.875472,1.0],[0.0,1.0,1.0],[-0.444072,1.03863,1.0],[-3.94773,1.01784,1.0],[-7.97996,0.975996,1.0],[-10.673,0.917401,1.0],[0.0,1.0,1.0],[1.22651,1.0559,1.0],[-1.89459,1.02934,1.0],[-5.54545,0.993046,1.0],[-8.48877,0.941628,1.0],[0.0,1.0,1.0],[3.24516,1.08292,1.0],[1.20522,1.0577,1.0],[-0.826224,1.01668,1.0],[-3.71884,0.946733,1.0],[0.0,1.0,1.0],[4.68802,1.12039,1.0],[3.23147,1.08619,1.0],[1.84476,1.04,1.0],[0.0970375,0.962298,1.0],[0.0,1.0,1.0],[5.36041,1.16313,1.0],[4.5937,1.10933,1.0],[3.83314,1.05056,1.0],[3.122,0.959876,1.0],[0.0,1.0,1.0],[5.22222,1.17824,1.0],[5.09129,1.1142,1.0],[4.99294,1.04813,1.0],[5.01485,0.957528,1.0],[0.0,1.0,1.0],[4.34382,1.18446,1.0],[4.9457,1.11351,1.0],[5.56715,1.04462,1.0],[6.27579,0.961892,1.0],[0.0,1.0,1.0],[3.5428,1.18985,1.0],[4.9116,1.11394,1.0],[6.11507,1.04098,1.0],[7.03638,0.964331,1.0],[0.0,1.0,1.0],[2.92641,1.20663,1.0],[4.57132,1.1281,1.0],[5.96964,1.04895,1.0],[6.98579,0.96261,1.0],[0.0,1.0,1.0],[2.07123,1.23257,1.0],[3.51736,1.15454,1.0],[4.85051,1.06995,1.0],[5.97805,0.971597,1.0],[0.0,1.0,1.0],[0.869122,1.26762,1.0],[2.22009,1.19021,1.0],[3.54297,1.10536,1.0],[4.31783,1.00254,1.0],[0.0,1.0,1.0],[-0.409355,1.31042,1.0],[0.778039,1.23845,1.0],[1.87845,1.15455,1.0],[1.53759,1.02961,1.0],[0.0,1.0,1.0],[-1.82067,1.35265,1.0],[-0.910751,1.28551,1.0],[-0.100378,1.18585,1.0],[0.0425375,1.01463,1.0],[0.0,1.0,1.0],[-3.26659,1.391,1.0],[-2.50117,1.33263,1.0],[-1.55789,1.18102,1.0],[-0.0853484,1.00594,1.0],[0.0,1.0,1.0],[-4.92446,1.43632,1.0],[-3.92066,1.35798,1.0],[-1.66274,1.11605,1.0],[-0.0358972,1.00178,1.0],[0.0,1.0,1.0],[-5.82474,1.46137,1.0],[-4.22466,1.34716,1.0],[-0.64525,1.04813,1.0],[-0.00357121,1.00023,1.0],[0.0,1.0,1.0],[-7.0672,1.47242,1.0],[-5.38667,1.32663,1.0],[-0.553542,1.02668,1.0],[-0.00188478,1.00008,1.0],[0.0,1.0,1.0],[-8.37522,1.43136,1.0],[-6.13631,1.28174,1.0],[-0.515332,1.01808,1.0],[-0.0015762,1.00005,1.0],[0.0,1.0,1.0],[-10.5196,1.39935,1.0],[-7.49316,1.24442,1.0],[-0.517621,1.01282,1.0],[-0.001445,1.00003,1.0],[0.0,1.0,1.0],[-10.5952,1.3534,1.0],[-7.81548,1.20414,1.0],[-0.63473,1.0111,1.0],[-0.00208267,1.00003,1.0],[0.0,1.0,1.0],[-10.879,1.32051,1.0],[-8.3374,1.18517,1.0],[-0.91817,1.01139,1.0],[-0.00474972,1.00003,1.0],[0.0,1.0,1.0],[-11.8094,1.29525,1.0],[-9.18818,1.17522,1.0],[-0.968552,1.01157,1.0],[-0.00411555,1.00003,1.0],[0.0,1.0,1.0],[-12.2038,1.27777,1.0],[-8.97374,1.15856,1.0],[-0.751018,1.00872,1.0],[-0.00250012,1.00002,1.0],[0.0,1.0,1.0],[-12.0564,1.2709,1.0],[-8.38288,1.15926,1.0],[-0.643806,1.00878,1.0],[-0.00202184,1.00002,1.0],[0.0,1.0,1.0],[-12.8403,1.25618,1.0],[-8.85664,1.14517,1.0],[-0.646111,1.00756,1.0],[-0.00195373,1.00001,1.0],[0.0,1.0,1.0],[-13.2604,1.25094,1.0],[-8.74013,1.11989,1.0],[-0.556009,1.00457,1.0],[-0.00173404,1.00001,1.0],[0.0,1.0,1.0],[-13.3939,1.24388,1.0],[-8.23916,1.11659,1.0],[-0.376536,1.00355,1.0],[-0.000916476,1.00001,1.0],[0.0,1.0,1.0],[-13.6578,1.24212,1.0],[-7.97883,1.11035,1.0],[-0.409859,1.00287,1.0],[-0.0018203,1.0,1.0],[0.0,1.0,1.0],[-15.7225,1.22414,1.0],[-10.2345,1.10217,1.0],[-0.968177,1.00427,1.0],[-0.00650675,1.00001,1.0],[0.0,1.0,1.0],[-16.1557,1.16423,1.0],[-12.721,1.06603,1.0],[-2.02337,1.00334,1.0],[-0.0134173,1.00001,1.0],[0.0,1.0,1.0],[-17.253,1.09714,1.0],[-15.785,1.02184,1.0],[-4.02264,0.996649,1.0],[-0.0279292,0.999956,1.0],[0.0,1.0,1.0],[-17.6206,1.04331,1.0],[-16.2039,0.99401,1.0],[-4.09728,0.990246,1.0],[-0.0269801,0.999896,1.0],[0.0,1.0,1.0],[-17.2302,0.987569,1.0],[-15.1656,0.964114,1.0],[-3.21398,0.983725,1.0],[-0.0202065,0.999807,1.0],[0.0,1.0,1.0],[-16.2184,0.943678,1.0],[-13.4633,0.938141,1.0],[-3.40639,0.971571,1.0],[-0.00923182,0.999563,1.0],[0.0,1.0,1.0],[-14.5653,0.909699,1.0],[-11.6873,0.915733,1.0],[-5.4654,0.942337,1.0],[-0.124331,0.998194,1.0],[0.0,1.0,1.0],[-11.5122,0.906891,1.0],[-9.31547,0.923874,1.0],[-6.12222,0.939832,1.0],[-0.337538,0.995963,1.0],[0.0,1.0,1.0],[-7.77619,0.92294,1.0]Line truncated
@@ -1,93 +0,0 @@
-Copyright 2022 The BIZ UDMincho Project Authors (https://github.com/googlefonts/morisawa-biz-ud-mincho)
-
-This Font Software is licensed under the SIL Open Font License, Version 1.1.
-This license is copied below, and is also available with a FAQ at:
-https://scripts.sil.org/OFL
-
-
-----------------------------------------------------------
-SIL OPEN FONT LICENSE Version 1.1 - 26 February 2007
-----------------------------------------------------------
-
-PREAMBLE
-The goals of the Open Font License (OFL) are to stimulate worldwide
-development of collaborative font projects, to support the font creation
-efforts of academic and linguistic communities, and to provide a free and
-open framework in which fonts may be shared and improved in partnership
-with others.
-
-The OFL allows the licensed fonts to be used, studied, modified and
-redistributed freely as long as they are not sold by themselves. The
-fonts, including any derivative works, can be bundled, embedded, 
-redistributed and/or sold with any software provided that any reserved
-names are not used by derivative works. The fonts and derivatives,
-however, cannot be released under any other type of license. The
-requirement for fonts to remain under this license does not apply
-to any document created using the fonts or their derivatives.
-
-DEFINITIONS
-"Font Software" refers to the set of files released by the Copyright
-Holder(s) under this license and clearly marked as such. This may
-include source files, build scripts and documentation.
-
-"Reserved Font Name" refers to any names specified as such after the
-copyright statement(s).
-
-"Original Version" refers to the collection of Font Software components as
-distributed by the Copyright Holder(s).
-
-"Modified Version" refers to any derivative made by adding to, deleting,
-or substituting -- in part or in whole -- any of the components of the
-Original Version, by changing formats or by porting the Font Software to a
-new environment.
-
-"Author" refers to any designer, engineer, programmer, technical
-writer or other person who contributed to the Font Software.
-
-PERMISSION & CONDITIONS
-Permission is hereby granted, free of charge, to any person obtaining
-a copy of the Font Software, to use, study, copy, merge, embed, modify,
-redistribute, and sell modified and unmodified copies of the Font
-Software, subject to the following conditions:
-
-1) Neither the Font Software nor any of its individual components,
-in Original or Modified Versions, may be sold by itself.
-
-2) Original or Modified Versions of the Font Software may be bundled,
-redistributed and/or sold with any software, provided that each copy
-contains the above copyright notice and this license. These can be
-included either as stand-alone text files, human-readable headers or
-in the appropriate machine-readable metadata fields within text or
-binary files as long as those fields can be easily viewed by the user.
-
-3) No Modified Version of the Font Software may use the Reserved Font
-Name(s) unless explicit written permission is granted by the corresponding
-Copyright Holder. This restriction only applies to the primary font name as
-presented to the users.
-
-4) The name(s) of the Copyright Holder(s) or the Author(s) of the Font
-Software shall not be used to promote, endorse or advertise any
-Modified Version, except to acknowledge the contribution(s) of the
-Copyright Holder(s) and the Author(s) or with their explicit written
-permission.
-
-5) The Font Software, modified or unmodified, in part or in whole,
-must be distributed entirely under this license, and must not be
-distributed under any other license. The requirement for fonts to
-remain under this license does not apply to any document created
-using the Font Software.
-
-TERMINATION
-This license becomes null and void if any of the above conditions are
-not met.
-
-DISCLAIMER
-THE FONT SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
-EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTIES OF
-MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT
-OF COPYRIGHT, PATENT, TRADEMARK, OR OTHER RIGHT. IN NO EVENT SHALL THE
-COPYRIGHT HOLDER BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
-INCLUDING ANY GENERAL, SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL
-DAMAGES, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
-FROM, OUT OF THE USE OR INABILITY TO USE THE FONT SOFTWARE OR FROM
-OTHER DEALINGS IN THE FONT SOFTWARE.
@@ -0,0 +1,466 @@
+{
+  "schema": 1,
+  "repo": "storytold/lightcraft",
+  "branch": "main",
+  "head": "2694d7089fbf4ada62c6738a7c62fecdfd5711fb",
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+  "unattributed_commits": 0,
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+  ]
+}
@@ -0,0 +1,23 @@
+# Contributor names for the About window (craftrules standards/contributors.md).
+#
+# Everyone who contributes is credited by GitHub username automatically. Anything more is up to
+# you: add YOUR OWN entry below, in your own PR (commit it yourself). Never add someone else; a
+# maintainer may add a person only when that person asked, recording where in consent_source.
+#
+# Easiest: python3 ../../craftrules/scripts/contributors.py --add-me . \
+#            [--real-name "Ada Lovelace"] [--display-name "Ada"] [--sync-github-name]
+#
+# Or copy this block, replacing your-github-username (every field is optional):
+#
+#   [people.your-github-username]
+#   real_name = "Your Name"        # shown when the viewer picks "Real name"
+#   display_name = "Nickname"      # shown when the viewer picks "Display name"
+#   sync_github_name = true        # or: use the name on your public GitHub profile as display name
+#
+# To remove your names, delete your entry (or set fields empty) in a PR. The next
+# contributors.py run, and the next build, drop them.
+
+[people.echelon]
+real_name = "Brandon Thomas"
+display_name = "Brandon Thomas"
+sync_github_name = false
@@ -10,6 +10,7 @@ workspace = true

 [dependencies]
 lightcraft-develop = { workspace = true }
+lightcraft-meta = { workspace = true }
 serde = { workspace = true }
 serde_json = { workspace = true }
 thiserror = { workspace = true }
@@ -0,0 +1,226 @@
+//! The library's folder tree: where on disk the imported photos live.
+//!
+//! A *folder* here is a folder holding at least one photo of the library (imported, not deleted,
+//! not merely browsed in Local; demo scenes have no folder). The tree lists those folders and the
+//! ones above them, never a folder that holds nothing of the library, with how many photos each
+//! holds — its subfolders included, like a year in By Date counts its months.
+//!
+//! Every folder is a row of its own, the ones above the imported photos included
+//! (`/Users` → `me` → `Pictures`), so a row is exactly the folder it names. A folder spelled two
+//! ways (`/` or `\`, repeated or trailing separators, `.`) is one folder (see
+//! [`crate::query::folder_key`]).
+//!
+//! Each disk is a *volume*, a top-level row of its own: a drive letter (`D:`), a Windows share
+//! (`//server/share`), a mounted disk or share (macOS `/Volumes/tokyo`, Linux `/media/me/usb`,
+//! `/mnt/disk`, `/run/user/1000/gvfs/smb-share:…`, `/net/host`) or, for everything else, the
+//! startup disk (`/`). Only the spelling of the stored paths tells them apart: no disk is
+//! touched, so a share that is asleep or gone lists and counts like one that is there, and the
+//! sidebar never waits on the network.
+//!
+//! Limits of reading only the stored spelling of a path: file names are compared as written
+//! (Windows folds case, other systems do not), so on a case-insensitive disk `/Volumes/tokyo` and
+//! `/Volumes/TOKYO` are two volumes here; and one place reached by two spellings
+//! (`/Volumes/Macintosh HD/Users/me` and `/Users/me`, `/media/me/usb` and `/run/media/me/usb`) is
+//! two rows. Each row is still consistent: choosing it shows exactly the photos it counts.
+//!
+//! This is the library's own view of its photos; browsing any folder on disk without importing
+//! is Local's job (see [`crate::local`]).
+
+use std::collections::{BTreeMap, HashMap};
+
+use serde::Serialize;
+
+use crate::query::{folder_key, folder_within, split_path};
+use crate::{Catalog, Source};
+
+/// Folder levels kept per photo. No real path comes near it; a deeper one is counted at its
+/// ancestor this many levels down, which bounds the tree's depth (and so every walk of it)
+/// whatever a catalog holds.
+pub const MAX_DEPTH: usize = 64;
+
+/// One row of the library's folder tree.
+#[derive(Clone, Debug, PartialEq, Serialize)]
+pub struct FolderNode {
+    /// What the row says: the folder's name; for a volume, its name (`nas`, `D:`,
+    /// `//server/share`, `/` for the startup disk).
+    pub name: String,
+    /// The folder the row stands for, written out from the names of the photos' paths (forward
+    /// slashes, no verbatim prefix); hand it back to [`crate::Filter::library_folder`] to see its
+    /// photos.
+    pub path: String,
+    /// Photos in this folder or any folder inside it.
+    pub count: usize,
+    /// Photos directly in this folder.
+    pub own: usize,
+    /// A disk rather than a folder in one; its `path` is where it is mounted.
+    pub volume: bool,
+    /// Whether choosing the row (`Filter::library_folder`) shows exactly its `count` photos. Not
+    /// so for the startup disk and for folders that hold other disks (`/Volumes`, `/mnt`…): their
+    /// path covers those disks' photos too, so choosing them is not offered.
+    pub selectable: bool,
+    pub children: Vec<FolderNode>,
+}
+
+/// A folder while the tree is being built (children by identity key).
+struct Level {
+    name: String,
+    path: String,
+    own: usize,
+    volume: bool,
+    children: Vec<String>,
+}
+
+/// Where a stored folder path lies: its volume and the folder names below it.
+struct Placed {
+    mount: String,
+    volume: String,
+    names: Vec<String>,
+}
+
+/// A gvfs mount's name made readable: `smb-share:server=tokyo,share=photos` → `photos on tokyo`;
+/// any other (`sftp:host=nas`) as it is.
+fn mount_name(n: &str) -> String {
+    let field = |key: &str| {
+        let rest = n.strip_prefix("smb-share:")?;
+        rest.split(',').find_map(|kv| kv.strip_prefix(key)?.strip_prefix('=')).filter(|v| !v.is_empty())
+    };
+    match (field("share"), field("server")) {
+        (Some(share), Some(server)) => format!("{share} on {server}"),
+        _ => n.to_string(),
+    }
+}
+
+/// The volume `dir` lies on and the folder names below it, read the way [`folder_key`] reads a
+/// path (so a row and the filter that chooses it never disagree). `None` for a path that is not
+/// absolute or names no share.
+fn place(dir: &str) -> Option<Placed> {
+    let sp = split_path(dir, false);
+    let names: Vec<&str> = sp.parts.iter().map(String::as_str).collect();
+    let named = |mount: String, volume: &str, used: usize| (mount, volume.to_string(), used);
+    let (mount, volume, used) = if sp.prefix.starts_with("//") {
+        // `//server/share`: a server alone (no share) is no place to keep photos
+        if sp.prefix.ends_with('/') {
+            return None;
+        }
+        named(sp.prefix.clone(), &sp.prefix, 0)
+    } else if !sp.prefix.is_empty() {
+        named(sp.prefix.clone(), &sp.prefix, 0)
+    } else if sp.absolute {
+        match names.as_slice() {
+            ["Volumes", n, ..] => named(format!("/Volumes/{n}"), n, 2),
+            ["run", "media", u, n, ..] => named(format!("/run/media/{u}/{n}"), n, 4),
+            ["media", u, n, ..] => named(format!("/media/{u}/{n}"), n, 3),
+            ["mnt", n, ..] => named(format!("/mnt/{n}"), n, 2),
+            // Linux desktops mount network places per user, naming server and share
+            ["run", "user", uid, "gvfs", n, ..] => named(format!("/run/user/{uid}/gvfs/{n}"), &mount_name(n), 5),
+            // NFS automounts: Linux `/net/<host>`, macOS `/Network/Servers/<host>`
+            ["net", host, ..] => named(format!("/net/{host}"), host, 2),
+            ["Network", "Servers", host, ..] => named(format!("/Network/Servers/{host}"), host, 3),
+            _ => named("/".to_string(), "/", 0),
+        }
+    } else {
+        return None;
+    };
+    Some(Placed { mount, volume, names: names.iter().skip(used).take(MAX_DEPTH).map(|n| n.to_string()).collect() })
+}
+
+/// The disk or share (`/Volumes/nas`, `D:`, `/` for the startup disk) a file-backed photo is on,
+/// from its stored path alone.
+pub fn volume_of(p: &crate::Photo) -> Option<String> {
+    let Source::File { path } = &p.source else { return None };
+    let dir = path.rfind(['/', '\\']).and_then(|i| path.get(..i.max(1)))?;
+    place(dir).map(|pl| folder_key(&pl.mount))
+}
+
+/// Whether `path` is a whole disk or share (`/`, `C:\`, `\\srv\share`, `/Volumes/nas`), not a
+/// folder in one.
+pub fn is_disk_root(path: &str) -> bool {
+    place(path).is_some_and(|p| p.names.is_empty())
+}
+
+/// Whether `path` is the startup disk's root (`/`), whose path also covers every other disk.
+pub fn is_startup_disk(path: &str) -> bool {
+    place(path).is_some_and(|p| p.names.is_empty() && p.mount == "/")
+}
+
+/// A folder named by its last two names (`photos/travel`), so two folders called `travel` are
+/// told apart; the path itself when it has no names (`/`).
+pub fn folder_label(path: &str) -> String {
+    let names: Vec<&str> = path.split(['/', '\\']).filter(|n| !n.is_empty()).collect();
+    if names.is_empty() { path.to_string() } else { names.iter().skip(names.len().saturating_sub(2)).copied().collect::<Vec<_>>().join("/") }
+}
+
+impl Catalog {
+    /// The library's volumes with their folders and photo counts: volumes by name
+    /// (case-insensitive), each folder with its subfolders the same way.
+    pub fn folder_tree(&self) -> Vec<FolderNode> {
+        // photos per containing folder, as spelled (sorted, so the spelling that names a folder
+        // never depends on hash order)
+        let mut dirs: BTreeMap<&str, usize> = BTreeMap::new();
+        for p in self.photos().filter(|p| p.in_library()) {
+            if let Source::File { path } = &p.source
+                && let Some(i) = path.rfind(['/', '\\'])
+                // a photo straight in the root has an empty folder part: the root itself
+                && let Some(dir) = path.get(..i.max(1))
+            {
+                *dirs.entry(dir).or_default() += 1;
+            }
+        }
+        let mut levels: HashMap<String, Level> = HashMap::new();
+        let mut roots: Vec<String> = Vec::new();
+        for (dir, n) in dirs {
+            let Some(placed) = place(dir) else { continue };
+            let vkey = folder_key(&placed.mount);
+            if !levels.contains_key(&vkey) {
+                levels.insert(
+                    vkey.clone(),
+                    Level { name: placed.volume.clone(), path: placed.mount.clone(), own: 0, volume: true, children: Vec::new() },
+                );
+                roots.push(vkey.clone());
+            }
+            let mut prefix = if placed.mount == "/" { String::new() } else { placed.mount.clone() };
+            let mut parent = vkey;
+            for name in &placed.names {
+                prefix.push('/');
+                prefix.push_str(name);
+                let key = folder_key(&prefix);
+                if !levels.contains_key(&key) {
+                    levels.insert(key.clone(), Level { name: name.clone(), path: prefix.clone(), own: 0, volume: false, children: Vec::new() });
+                    if let Some(l) = levels.get_mut(&parent) {
+                        l.children.push(key.clone());
+                    }
+                }
+                parent = key;
+            }
+            if let Some(l) = levels.get_mut(&parent) {
+                l.own += n;
+            }
+        }
+        let mut tree: Vec<FolderNode> = roots.iter().filter_map(|k| build(k, &levels)).collect();
+        sort(&mut tree);
+        // a folder that holds another disk's mount covers that disk's photos too
+        let mounts: Vec<String> = tree.iter().filter(|v| v.path != "/").map(|v| v.path.clone()).collect();
+        mark_selectable(&mut tree, &mounts);
+        tree
+    }
+}
+
+/// The node for `key` with everything below it (at most [`MAX_DEPTH`] deep).
+fn build(key: &str, levels: &HashMap<String, Level>) -> Option<FolderNode> {
+    let l = levels.get(key)?;
+    let mut children: Vec<FolderNode> = l.children.iter().filter_map(|k| build(k, levels)).collect();
+    sort(&mut children);
+    let count = l.own + children.iter().map(|c| c.count).sum::<usize>();
+    Some(FolderNode { name: l.name.clone(), path: l.path.clone(), count, own: l.own, volume: l.volume, selectable: true, children })
+}
+
+fn mark_selectable(nodes: &mut [FolderNode], mounts: &[String]) {
+    for n in nodes {
+        n.selectable = !(n.volume && n.path == "/") && (n.volume || !mounts.iter().any(|m| folder_within(m, &n.path)));
+        mark_selectable(&mut n.children, mounts);
+    }
+}
+
+fn sort(v: &mut [FolderNode]) {
+    v.sort_by(|a, b| a.name.to_lowercase().cmp(&b.name.to_lowercase()).then_with(|| a.name.cmp(&b.name)));
+}
@@ -14,6 +14,7 @@
 #![deny(clippy::unwrap_used, clippy::expect_used, clippy::panic, clippy::unimplemented, clippy::todo, clippy::unreachable)]

 pub mod dates;
+pub mod folders;
 pub mod journal;
 pub mod keywords;
 pub mod local;
@@ -29,13 +30,14 @@ use std::collections::BTreeMap;
 use std::sync::Arc;

 pub use dates::{DateRun, GroupBy};
+pub use folders::FolderNode;
 pub use journal::{Journal, LoadReport, PersistStats, SnapshotPolicy, SnapshotTiming};
 pub use keywords::KeywordNode;
 use lightcraft_develop::DevelopSettings;
 pub use local::{DEFAULT_FORGET_DAYS, ForgetPlan, folder_of};
 pub use lock::{LibraryLock, LockError, LockOwner};
 pub use model::*;
-pub use query::{DateGroup, Filter, RatingOp, Sort, SortKey};
+pub use query::{DateGroup, Filter, Person, RatingOp, Sort, SortKey, mix64};
 pub use rules::{Match, Rule, RuleSet};
 use serde::{Deserialize, Serialize};
 pub use store::{FsStore, MemStore, Store};
@@ -612,6 +614,22 @@ impl Catalog {
        Op::Batch { ops }
    }

+    /// [`Self::delete_permanently_ops`] for several photos at once. One op list built against the
+    /// catalog as it is now: albums lose all of them in one write each, and stacks are shortened
+    /// (or dissolved) once, however many of their photos go.
+    pub fn delete_photos_permanently_ops(&self, ids: &[PhotoId]) -> Op {
+        let gone: std::collections::HashSet<PhotoId> = ids.iter().copied().collect();
+        let mut ops: Vec<Op> = self
+            .albums
+            .values()
+            .filter(|a| a.photos.iter().any(|p| gone.contains(p)))
+            .map(|a| Op::SetAlbumPhotos { id: a.id, photos: a.photos.iter().copied().filter(|p| !gone.contains(p)).collect() })
+            .collect();
+        ops.extend(self.remove_from_stacks_ops(ids));
+        ops.extend(gone.iter().map(|id| Op::RemovePhoto { id: *id }));
+        Op::Batch { ops }
+    }
+
    // ---- persistence

    /// Full snapshot as JSON.
@@ -655,6 +673,8 @@ mod tests;
 #[cfg(test)]
 mod tests_background;
 #[cfg(test)]
+mod tests_folders;
+#[cfg(test)]
 mod tests_format_version;
 #[cfg(test)]
 mod tests_journal;
@@ -2,7 +2,7 @@

 use std::sync::Arc;

-use lightcraft_develop::DevelopSettings;
+use lightcraft_develop::{DevelopSettings, WbMode};
 use serde::{Deserialize, Serialize};

 #[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
@@ -183,6 +183,11 @@ pub struct Meta {
    pub copyright_url: String,
    pub creator: String,
    pub keywords: Vec<String>,
+    /// Face/pet/focus regions read from XMP (MWG-RS), on the upright (EXIF-oriented) photo.
+    /// Removing or resizing one edits the catalog only; LightCraft never writes regions to XMP.
+    /// Left out of the catalog JSON when empty (most photos), so older catalogs read unchanged.
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub regions: Vec<lightcraft_meta::Region>,
 }

 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
@@ -331,6 +336,13 @@ impl Photo {
    pub fn develops_raw(&self) -> bool {
        self.kind == MediaKind::Raw && self.preview_only.is_none()
    }
+    /// The current ARW, NEF, RW2, RAF and CR3 readers have vendor WB multipliers but no measured camera
+    /// illuminant. Use adjustments relative to the camera's as-shot look, as for rendered
+    /// photographs (the engine's `camera_preview::file_local_look` covers the same formats; RWL and
+    /// RAW are Leica's and the oldest Panasonic bodies' names for RW2 files).
+    pub fn relative_wb(&self) -> bool {
+        self.develops_raw() && ["ARW", "NEF", "NRW", "RW2", "RWL", "RAW", "RAF", "CR3"].iter().any(|f| self.format.eq_ignore_ascii_case(f))
+    }
    /// The develop settings import gave this photo: [`Photo::camera_defaults`], or the user's
    /// default preset applied on top of them ([`Photo::import_look`]).
    pub fn import_defaults(&self) -> DevelopSettings {
@@ -342,7 +354,8 @@ impl Photo {
    /// The built-in defaults for this photo, before any user default preset: raws start from
    /// their as-shot white balance; embedded lens corrections on when the file has them.
    pub fn camera_defaults(&self) -> DevelopSettings {
-        let mut d = match self.as_shot_wb {
+        let wb = if self.relative_wb() { Some((6500.0, 0.0)) } else { self.as_shot_wb };
+        let mut d = match wb {
            Some((t, tint)) => DevelopSettings::for_raw(t, tint),
            None => DevelopSettings::default(),
        };
@@ -357,7 +370,12 @@ impl Photo {
    }
    /// Edited by the user: settings differ from what import gave the photo.
    pub fn is_edited(&self) -> bool {
-        *self.develop != self.import_defaults() && !self.develop.is_unedited()
+        let mut defaults = self.import_defaults();
+        // As Shot reads the source's current WB; stored numbers can predate a decoder update.
+        if self.develop.wb.mode == WbMode::AsShot && defaults.wb.mode == WbMode::AsShot {
+            defaults.wb = self.develop.wb;
+        }
+        *self.develop != defaults && !self.develop.is_unedited()
    }
    /// Capture time if known, else import time (sort key).
    pub fn date(&self) -> &str {
@@ -415,4 +433,35 @@ mod edited_tests {
        p.develop = Arc::new(DevelopSettings::default());
        assert!(!p.is_edited(), "a full reset is unedited too");
    }
+
+    #[test]
+    fn supported_raws_use_relative_white_balance() {
+        for (name, format, relative) in [
+            ("a.arw", "ARW", true),
+            ("a.nef", "NEF", true),
+            ("a.nrw", "nrw", true),
+            ("a.rw2", "RW2", true),
+            ("a.rwl", "RWL", true),
+            ("a.raw", "RAW", true),
+            ("a.raf", "rAf", true),
+            ("a.cr3", "cr3", true),
+            ("a.dng", "DNG", false),
+        ] {
+            let mut p = Photo::new(PhotoId(1), Source::Demo { scene: 0 }, name, format, 10, 10, "2026-10-01T00:00:00");
+            p.kind = MediaKind::Raw;
+            p.as_shot_wb = Some((5200.0, 4.0));
+            assert_eq!(p.relative_wb(), relative, "{format}");
+            let wb = p.camera_defaults().wb;
+            assert_eq!((wb.temp, wb.tint), if relative { (6500.0, 0.0) } else { (5200.0, 4.0) }, "{format}");
+            p.develop = Arc::new(DevelopSettings::for_raw(5200.0, 4.0));
+            assert!(!p.is_edited(), "{format}: old As Shot values are not an edit");
+            let mut custom = (*p.develop).clone();
+            custom.wb.mode = WbMode::Custom;
+            p.develop = Arc::new(custom);
+            assert!(p.is_edited(), "{format}: Custom WB is still an edit");
+            // shown from the embedded preview: a rendered image, not a relative-WB raw
+            p.preview_only = Some("unsupported".into());
+            assert!(!p.relative_wb());
+        }
+    }
 }
@@ -37,8 +37,14 @@ pub struct Filter {
    pub deleted: bool,
    /// Capture date prefix (`2026`, `2026-04`, `2026-04-12`).
    pub date: Option<String>,
+    /// A folder the library's photos were imported from: those photos and the ones imported from
+    /// the folders inside it (see [`crate::folders`]). Photos only browsed in Local are never part
+    /// of it, unlike [`Filter::folder`].
+    pub library_folder: Option<String>,
    /// A keyword; hierarchical keywords match their children too (`travel` finds `travel|italy`).
    pub keyword: Option<String>,
+    /// A person: photos with a named face region of this name (case-insensitive), as read from XMP.
+    pub person: Option<String>,
    pub camera: Option<String>,
    /// Lens (case-insensitive substring).
    pub lens: Option<String>,
@@ -70,6 +76,9 @@ pub enum SortKey {
    FileName,
    Rating,
    FileSize,
+    /// A shuffle fixed by [`Sort::seed`]: the same seed always gives the same order, and photos
+    /// added or edited later never reshuffle the others. Pick a new seed to reshuffle.
+    Random,
 }

 #[derive(Clone, Copy, Debug, PartialEq, Eq, Serialize, Deserialize)]
@@ -79,14 +88,30 @@ pub struct Sort {
    pub ascending: bool,
    /// Date headers in the grid (date sort keys only).
    pub group: crate::GroupBy,
+    /// Which shuffle [`SortKey::Random`] gives (ignored by the other keys).
+    pub seed: u64,
 }

 impl Default for Sort {
    fn default() -> Self {
-        Sort { key: SortKey::CaptureDate, ascending: false, group: crate::GroupBy::Auto }
+        Sort { key: SortKey::CaptureDate, ascending: false, group: crate::GroupBy::Auto, seed: 0 }
    }
 }

+/// splitmix64 finaliser: a stateless, platform-independent mix (no RNG state, no `rand` version
+/// to drift), so a seed names the same shuffle on every machine.
+pub fn mix64(x: u64) -> u64 {
+    let mut z = x.wrapping_add(0x9E37_79B9_7F4A_7C15);
+    z = (z ^ (z >> 30)).wrapping_mul(0xBF58_476D_1CE4_E5B9);
+    z = (z ^ (z >> 27)).wrapping_mul(0x94D0_49BB_1331_11EB);
+    z ^ (z >> 31)
+}
+
+/// A photo's place in the shuffle for `seed`.
+fn shuffle_rank(seed: u64, id: PhotoId) -> u64 {
+    mix64(mix64(seed) ^ id.0)
+}
+
 fn token_matches(p: &Photo, tok: &str) -> bool {
    let t = tok.to_lowercase();
    if let Some((field, val)) = t.split_once(':') {
@@ -113,6 +138,7 @@ fn token_matches(p: &Photo, tok: &str) -> bool {
            "camera" => p.meta.camera.to_lowercase().contains(val),
            "lens" => p.meta.lens.to_lowercase().contains(val),
            "keyword" | "kw" => p.meta.keywords.iter().any(|k| crate::keywords::is_under(k, val)),
+            "person" | "who" => has_person(p, val),
            "type" | "kind" => format!("{:?}", p.kind).eq_ignore_ascii_case(val),
            "edited" => (val == "true" || val == "yes") == p.is_edited(),
            "date" => p.date().starts_with(val),
@@ -125,6 +151,12 @@ fn token_matches(p: &Photo, tok: &str) -> bool {
    hay.iter().any(|h| h.to_lowercase().contains(&t)) || p.meta.keywords.iter().any(|k| k.to_lowercase().contains(&t))
 }

+/// Whether `p` has a named face region called `name` (case-insensitive).
+fn has_person(p: &Photo, name: &str) -> bool {
+    let name = name.trim().to_lowercase();
+    p.meta.regions.iter().any(|r| r.kind == lightcraft_meta::RegionKind::Face && r.name.as_deref().is_some_and(|n| n.to_lowercase() == name))
+}
+
 impl Filter {
    /// Human-readable summary of the active rules (smart album tooltips, `album.list`).
    pub fn describe(&self) -> String {
@@ -152,9 +184,15 @@ impl Filter {
        if let Some(e) = self.edited {
            v.push(if e { "edited".into() } else { "unedited".into() });
        }
-        for (name, val) in
-            [("keyword", &self.keyword), ("camera", &self.camera), ("lens", &self.lens), ("date", &self.date), ("imported", &self.imported)]
-        {
+        for (name, val) in [
+            ("keyword", &self.keyword),
+            ("person", &self.person),
+            ("camera", &self.camera),
+            ("lens", &self.lens),
+            ("date", &self.date),
+            ("folder", &self.library_folder),
+            ("imported", &self.imported),
+        ] {
            if let Some(x) = val {
                v.push(format!("{name} {x}"));
            }
@@ -180,6 +218,19 @@ impl Filter {
    }

    pub fn matches(&self, p: &Photo, cat: &Catalog) -> bool {
+        self.matches_in(p, cat, self.library_root().as_deref())
+    }
+
+    /// [`Filter::library_folder`] as a folder identity ([`folder_key`]); `None` without a choice.
+    fn library_root(&self) -> Option<String> {
+        // as given: a folder may be named with spaces at its edge, and trimming would make it
+        // another folder
+        self.library_folder.as_deref().filter(|d| !d.trim().is_empty()).map(folder_key)
+    }
+
+    /// [`Filter::matches`] with the library folder already turned into its identity, so a query
+    /// over a big library does that once, not once per photo.
+    fn matches_in(&self, p: &Photo, cat: &Catalog, root: Option<&str>) -> bool {
        if p.deleted != self.deleted {
            return false;
        }
@@ -252,6 +303,11 @@ impl Filter {
        {
            return false;
        }
+        if let Some(root) = root
+            && !photo_in_root(p, root)
+        {
+            return false;
+        }
        if let Some(d) = &self.imported
            && !p.imported.starts_with(d.as_str())
        {
@@ -267,6 +323,11 @@ impl Filter {
        {
            return false;
        }
+        if let Some(n) = &self.person
+            && !has_person(p, n)
+        {
+            return false;
+        }
        if let Some(c) = &self.camera
            && !p.meta.camera.eq_ignore_ascii_case(c)
        {
@@ -279,7 +340,8 @@ impl Filter {
 impl Catalog {
    /// Photos matching `filter`, in `sort` order (ties broken by id for stability).
    pub fn query(&self, filter: &Filter, sort: &Sort) -> Vec<PhotoId> {
-        let mut v: Vec<&Photo> = self.photos().map(|p| p.as_ref()).filter(|p| filter.matches(p, self)).collect();
+        let root = filter.library_root();
+        let mut v: Vec<&Photo> = self.photos().map(|p| p.as_ref()).filter(|p| filter.matches_in(p, self, root.as_deref())).collect();
        v.sort_by(|a, b| {
            let o = match sort.key {
                SortKey::CaptureDate => a.date().cmp(b.date()),
@@ -288,6 +350,7 @@ impl Catalog {
                SortKey::FileName => a.file_name.to_lowercase().cmp(&b.file_name.to_lowercase()),
                SortKey::Rating => a.rating.cmp(&b.rating),
                SortKey::FileSize => a.file_size.cmp(&b.file_size),
+                SortKey::Random => shuffle_rank(sort.seed, a.id).cmp(&shuffle_rank(sort.seed, b.id)),
            }
            .then(a.id.cmp(&b.id));
            if sort.ascending { o } else { o.reverse() }
@@ -330,6 +393,55 @@ impl Catalog {
        }
        m.into_iter().collect()
    }
+
+    /// The people named on faces in the library (MWG regions read from XMP): how many photos each
+    /// appears in and the photo showing their largest face (for a card's picture). Most photos first,
+    /// then by name. Names that differ only in case are one person, shown as first seen; a person
+    /// twice in one photo counts once.
+    pub fn people(&self) -> Vec<Person> {
+        self.people_in(&Filter::default())
+    }
+
+    /// [`Self::people`] among the photos `filter` lets through (its `person` is ignored): what the
+    /// People view offers while other filters (a date, a rating, an album…) are active, so picking
+    /// a person never ends in an empty grid.
+    pub fn people_in(&self, filter: &Filter) -> Vec<Person> {
+        let filter = Filter { person: None, ..filter.clone() };
+        let mut m: std::collections::HashMap<String, (Person, f64)> = Default::default();
+        let root = filter.library_root();
+        for p in self.photos().filter(|p| filter.matches_in(p, self, root.as_deref())) {
+            let mut seen: Vec<String> = Vec::new();
+            for r in p.meta.regions.iter().filter(|r| r.kind == lightcraft_meta::RegionKind::Face) {
+                let Some(name) = r.name.as_deref().map(str::trim).filter(|n| !n.is_empty()) else { continue };
+                let key = name.to_lowercase();
+                // the face's size in pixels of the photo
+                let area = (r.rect.x1 - r.rect.x0) * (r.rect.y1 - r.rect.y0) * p.width as f64 * p.height as f64;
+                let (person, best) =
+                    m.entry(key.clone()).or_insert_with(|| (Person { name: name.to_string(), count: 0, photo: p.id, face: r.rect }, area));
+                if !seen.contains(&key) {
+                    person.count += 1;
+                    seen.push(key);
+                }
+                if area > *best || (area == *best && p.id < person.photo) {
+                    (person.photo, person.face, *best) = (p.id, r.rect, area);
+                }
+            }
+        }
+        let mut v: Vec<Person> = m.into_values().map(|(p, _)| p).collect();
+        v.sort_by(|a, b| b.count.cmp(&a.count).then_with(|| a.name.to_lowercase().cmp(&b.name.to_lowercase())));
+        v
+    }
+}
+
+/// A person named on faces in the library ([`Catalog::people`]).
+#[derive(Clone, Debug, PartialEq)]
+pub struct Person {
+    pub name: String,
+    /// Photos they appear in.
+    pub count: usize,
+    /// The photo with their largest face, and that face (normalized, in the photo's upright frame).
+    pub photo: PhotoId,
+    pub face: lightcraft_meta::Rect,
 }

 #[derive(Clone, Debug, PartialEq, Serialize)]
@@ -351,12 +463,18 @@ pub fn in_folder(path: &str, dir: &str, deep: bool) -> bool {
    !rest.is_empty() && (deep || !rest.contains(['/', '\\']))
 }

-/// A folder path's identity, for telling whether two spellings name the same folder: `/` and
-/// `\\` are both separators, repeated separators, `.` and a trailing separator are dropped,
-/// `..` is resolved lexically, a Windows verbatim prefix (`\\?\`) is removed and the drive
-/// letter lower-cased; on Windows (case-insensitive file names) the whole path is lower-cased.
-/// No file-system access: the paths compared should already be absolute.
-pub fn folder_key(path: &str) -> String {
+/// A path read the way [`folder_key`] reads it: the part `..` can't climb above (`//server/share`,
+/// `c:`; empty for `/` and relative paths), the names below it, and whether it is absolute.
+pub(crate) struct SplitPath {
+    pub prefix: String,
+    pub parts: Vec<String>,
+    pub absolute: bool,
+}
+
+/// Both separators, repeated separators (also between a server and its share), `.` and a
+/// trailing separator dropped, `..` resolved lexically, a Windows verbatim prefix removed;
+/// `lower_drive` lower-cases a drive letter (the identity does, a display name wants it as is).
+pub(crate) fn split_path(path: &str, lower_drive: bool) -> SplitPath {
    let mut s = path.replace('\\', "/");
    if let Some(rest) = s.strip_prefix("//?/").or_else(|| s.strip_prefix("//./")) {
        s = match rest.strip_prefix("UNC/") {
@@ -364,28 +482,39 @@ pub fn folder_key(path: &str) -> String {
            None => rest.to_string(),
        };
    }
-    // the part `..` can't climb above: `//server/share`, `c:` or `/`
    let (prefix, rest) = if let Some(unc) = s.strip_prefix("//").filter(|u| !u.is_empty() && !u.starts_with('/')) {
-        let mut it = unc.splitn(3, '/');
-        let (server, share, rest) = (it.next().unwrap_or(""), it.next().unwrap_or(""), it.next().unwrap_or(""));
-        (format!("//{server}/{share}"), rest.to_string())
-    } else if s.len() >= 2 && s.as_bytes()[1] == b':' && s.as_bytes()[0].is_ascii_alphabetic() {
-        (s[..2].to_ascii_lowercase(), s[2..].to_string())
+        let mut segs = unc.split('/').filter(|x| !x.is_empty());
+        let (server, share) = (segs.next().unwrap_or(""), segs.next().unwrap_or(""));
+        (format!("//{server}/{share}"), segs.collect::<Vec<_>>().join("/"))
+    } else if let (true, Some(drive), Some(rest)) = (matches!(s.as_bytes(), [a, b':', ..] if a.is_ascii_alphabetic()), s.get(..2), s.get(2..)) {
+        (if lower_drive { drive.to_ascii_lowercase() } else { drive.to_string() }, rest.to_string())
    } else {
        (String::new(), s.clone())
    };
    let absolute = rest.starts_with('/') || !prefix.is_empty();
-    let mut parts: Vec<&str> = Vec::new();
+    let mut parts: Vec<String> = Vec::new();
    for c in rest.split('/') {
        match c {
            "" | "." => {}
-            ".." if parts.last().is_some_and(|p| *p != "..") => {
+            ".." if parts.last().is_some_and(|p| p != "..") => {
                parts.pop();
            }
            ".." if absolute => {}
-            c => parts.push(c),
+            c => parts.push(c.to_string()),
        }
    }
+    SplitPath { prefix, parts, absolute }
+}
+
+/// A folder path's identity, for telling whether two spellings name the same folder: `/` and
+/// `\\` are both separators, repeated separators, `.` and a trailing separator are dropped,
+/// `..` is resolved lexically, a Windows verbatim prefix (`\\?\`) is removed and the drive
+/// letter lower-cased; on Windows (case-insensitive file names) the whole path is lower-cased.
+/// File names are otherwise compared as written, so on a case-insensitive disk elsewhere
+/// (macOS, a Samba share) two spellings that differ in case are two folders here.
+/// No file-system access: the paths compared should already be absolute.
+pub fn folder_key(path: &str) -> String {
+    let SplitPath { prefix, parts, absolute } = split_path(path, true);
    let key = if absolute { format!("{prefix}/{}", parts.join("/")) } else { parts.join("/") };
    if cfg!(windows) { key.to_lowercase() } else { key }
 }
@@ -393,8 +522,51 @@ pub fn folder_key(path: &str) -> String {
 /// Whether `path` is folder `root` or lies somewhere inside it, however either is spelled
 /// (see [`folder_key`]).
 pub fn folder_within(path: &str, root: &str) -> bool {
-    let (p, r) = (folder_key(path), folder_key(root));
-    p == r || (p.starts_with(&r) && (r.ends_with('/') || p[r.len()..].starts_with('/')))
+    key_within(&folder_key(path), &folder_key(root))
+}
+
+/// The names below folder `root` that lead to `path`, as the caller spelled them (`None` when
+/// `path` is not at or inside `root`; empty when it is `root`). Compared by [`folder_key`], but
+/// the names keep their case, which the key lowers on Windows.
+pub fn folder_rest(path: &str, root: &str) -> Option<Vec<String>> {
+    if !key_within(&folder_key(path), &folder_key(root)) {
+        return None;
+    }
+    let depth = split_path(root, false).parts.len();
+    Some(split_path(path, false).parts.into_iter().skip(depth).collect())
+}
+
+/// Whether a library photo (not one only browsed in Local) lies in the folder whose
+/// [`folder_key`] is `root`. A plain POSIX path (no `\`, `.`, `..`, repeated or trailing
+/// separators) is its own identity, so it is read without building a key for it: the check runs
+/// for every photo of the library on each refresh, and this keeps it cheap.
+pub(crate) fn photo_in_root(p: &Photo, root: &str) -> bool {
+    if p.local {
+        return false;
+    }
+    let crate::Source::File { path } = &p.source else { return false };
+    let plain = path.starts_with('/')
+        && !path.starts_with("//")
+        && !path.ends_with('/')
+        && !path.contains(['\\'])
+        && !path.contains("//")
+        && !path.contains("/.");
+    if !cfg!(windows) && plain && root.starts_with('/') && !root.starts_with("//") {
+        let r = root.trim_end_matches('/');
+        return path.strip_prefix(r).is_some_and(|rest| rest.starts_with('/'));
+    }
+    crate::local::folder_of(p).is_some_and(|f| key_within(&f, root))
+}
+
+/// [`folder_within`] for two paths already turned into their [`folder_key`].
+pub(crate) fn key_within(p: &str, r: &str) -> bool {
+    // `.` or `a/..` name no folder: not "everything"
+    if r.is_empty() {
+        return false;
+    }
+    // a disk's root key ends in `/` (`c:/`, `//srv/share/`), a folder's does not: same folder
+    let (p, r) = (p.trim_end_matches('/'), r.trim_end_matches('/'));
+    p == r || p.strip_prefix(r).is_some_and(|rest| rest.starts_with('/'))
 }

 /// The kind of Photo Merge result a file is, from the name merges give it (`IMG_1-HDR.dng`,
@@ -7,7 +7,7 @@
 use serde::{Deserialize, Serialize};
 use serde_json::Value;

-use crate::{Catalog, Photo};
+use crate::{Catalog, Photo, Source};

 #[derive(Clone, Copy, Debug, Default, PartialEq, Eq, Serialize, Deserialize)]
 #[serde(rename_all = "lowercase")]
@@ -62,6 +62,7 @@ pub const FIELDS: &[(&str, &str, Kind)] = &[
    ("keywords", "Keywords", Kind::Keywords),
    ("text", "Any Searchable Text", Kind::Text),
    ("fileName", "Filename", Kind::Text),
+    ("filePath", "File Path", Kind::Text),
    ("format", "File Format", Kind::Text),
    ("title", "Title", Kind::Text),
    ("caption", "Caption", Kind::Text),
@@ -304,6 +305,20 @@ impl Rule {
                text(&all)
            }
            "fileName" => text(&p.file_name),
+            "filePath" => {
+                // `/` and `\` both separate, whatever platform the catalog came from; demo photos have no path
+                let path = match &p.source {
+                    Source::File { path } => path.replace('\\', "/"),
+                    Source::Demo { .. } => String::new(),
+                };
+                let want = want.replace('\\', "/");
+                match op {
+                    // the whole string, spaces included (not word by word like the other text fields)
+                    "contains" => !want.trim().is_empty() && path.to_lowercase().contains(want.trim()),
+                    "notContains" => want.trim().is_empty() || !path.to_lowercase().contains(want.trim()),
+                    _ => text_op(op, &path, &want),
+                }
+            }
            "format" => text(&p.format),
            "title" => text(&m.title),
            "caption" => text(&m.caption),
@@ -445,6 +460,17 @@ mod tests {
        );
        no(json!({"rules": [{"field": "keywords", "op": "isEmpty"}]}));
        yes(json!({"rules": [{"field": "fileName", "op": "startsWith", "value": "img_"}, {"field": "fileName", "op": "endsWith", "value": ".cr2"}]}));
+        // file path: the whole string (spaces included), either separator, case-insensitive
+        let mut fp = photo(3);
+        fp.source = Source::File { path: "D:\\Photos\\Aliah Ira Polanco-Grylls\\2026\\IMG_0042.CR2".into() };
+        let fpm = |v: serde_json::Value| rs(v).matches(&fp, &cat);
+        assert!(fpm(json!({"rules": [{"field": "filePath", "op": "contains", "value": "/Aliah Ira Polanco-Grylls/"}]})));
+        assert!(!fpm(json!({"rules": [{"field": "filePath", "op": "contains", "value": "/Ira Aliah/"}]})));
+        assert!(!fpm(json!({"rules": [{"field": "filePath", "op": "contains", "value": "Polanco Grylls"}]})));
+        assert!(fpm(json!({"rules": [{"field": "filePath", "op": "notContains", "value": "/Other/"}]})));
+        assert!(fpm(json!({"rules": [{"field": "filePath", "op": "startsWith", "value": "d:/photos/"}]})));
+        no(json!({"rules": [{"field": "filePath", "op": "contains", "value": "/Aliah/"}]})); // demo photo has no path
+        yes(json!({"rules": [{"field": "filePath", "op": "isEmpty"}]}));
        yes(json!({"rules": [{"field": "camera", "op": "contains", "value": "x2"}, {"field": "title", "op": "isEmpty"}]}));
        yes(json!({"rules": [{"field": "iso", "op": "between", "value": [800, 3200]}, {"field": "aperture", "op": "lte", "value": "f/4"}]}));
        yes(json!({"rules": [{"field": "megapixels", "op": "gte", "value": 24}]}));
@@ -1,11 +1,23 @@
 //! Crash-safe writes of user-visible files: exports, renders, DNG conversions, smart previews and
 //! XMP sidecars all go through here (the catalog's own files use [`crate::store::FsStore`]).
 //!
+//! **Write policy** (issue #134): what can't be recreated — originals, XMP sidecars, the catalog,
+//! settings, DNGs that replace raws, smart previews (the only stand-in while an original is
+//! offline), an edit copy that becomes a library photo — is written **durably**: synced to disk
+//! before it counts as written. What can always be made again from the originals — exports,
+//! renders, screenshots, merge previews — is written **atomically** only: a half-written file
+//! never replaces a good one, but there is no per-file sync (on a USB drive or a NAS that sync
+//! dominates a large export).
+//!
 //! - [`write_atomic`] replaces a file so that after a crash, a full disk or an unplugged drive
 //!   either the old or the complete new content is there — never a truncated mix. The content
 //!   goes to a new temp file in the same folder (unique name, `create_new`), is synced to disk and
 //!   renamed over the target; then the folder is synced (POSIX). Any failure removes the temp
 //!   file and leaves the target as it was.
+//! - [`write_atomic_nosync`] is the same temp file + rename without the two syncs, for
+//!   recreatable outputs only: a failed write still removes the temp file and leaves the target as
+//!   it was, but after a power cut the new file may be lost (on some file systems left empty) —
+//!   it is then simply exported again.
 //! - [`write_new`] / [`write_new_unique`] write a file that must not exist yet: the same temp file
 //!   and sync, plus a read-back check, and the file then appears under its final name **without
 //!   replacing anything** (a hard link, which fails on a taken name; a check-then-rename where the
@@ -21,6 +33,19 @@ use std::sync::atomic::{AtomicU64, Ordering};

 thread_local! {
    static FAIL_AFTER: Cell<Option<u64>> = const { Cell::new(None) };
+    static SYNCS: Cell<u64> = const { Cell::new(0) };
+}
+
+/// How many file and folder syncs this module made **on the calling thread** (for tests: a
+/// durable write path syncs, a recreatable output doesn't).
+#[doc(hidden)]
+pub fn syncs_on_this_thread() -> u64 {
+    SYNCS.with(Cell::get)
+}
+
+fn sync_file(f: &File) -> io::Result<()> {
+    SYNCS.with(|c| c.set(c.get() + 1));
+    f.sync_all()
 }

 /// Fault injection for tests (in any crate): while the returned guard lives, every write made by
@@ -78,7 +103,7 @@ fn parent_of(path: &Path) -> &Path {
 /// where NTFS journals the rename itself, so errors are ignored.
 pub fn sync_dir(dir: &Path) {
    if let Ok(d) = File::open(dir) {
-        let _ = d.sync_all();
+        let _ = sync_file(&d);
    }
 }

@@ -100,9 +125,9 @@ fn create_temp(path: &Path) -> io::Result<(PathBuf, File)> {
    Err(io::Error::new(io::ErrorKind::AlreadyExists, format!("no free temp file name in {}", dir.display())))
 }

-/// Write a temp file next to `path` with what `fill` writes, synced to disk. On failure the temp
-/// file is removed. Returns its path and length.
-fn write_temp(path: &Path, fill: &mut dyn FnMut(&mut dyn Write) -> io::Result<()>) -> io::Result<(PathBuf, u64)> {
+/// Write a temp file next to `path` with what `fill` writes, synced to disk when `sync`. On
+/// failure the temp file is removed. Returns its path and length.
+fn write_temp(path: &Path, sync: bool, fill: &mut dyn FnMut(&mut dyn Write) -> io::Result<()>) -> io::Result<(PathBuf, u64)> {
    let (tmp, file) = create_temp(path)?;
    let r = (|| {
        let limit = FAIL_AFTER.with(Cell::get);
@@ -111,7 +136,9 @@ fn write_temp(path: &Path, fill: &mut dyn FnMut(&mut dyn Write) -> io::Result<()
        w.flush()?;
        let n = w.n;
        let f = w.inner.into_inner().map_err(|e| e.into_error())?;
-        f.sync_all()?;
+        if sync {
+            sync_file(&f)?;
+        }
        Ok(n)
    })();
    match r {
@@ -132,12 +159,26 @@ pub fn write_atomic(path: &Path, data: &[u8]) -> io::Result<()> {
 /// [`write_atomic`] with streamed content: `fill` writes it (an error aborts and leaves the old
 /// file). Returns the length written.
 pub fn write_atomic_with(path: &Path, fill: &mut dyn FnMut(&mut dyn Write) -> io::Result<()>) -> io::Result<u64> {
-    let (tmp, n) = write_temp(path, fill)?;
+    replace_with(path, true, fill)
+}
+
+/// Replace (or create) `path` with `data` atomically but **without syncing** it to disk — only for
+/// outputs that can always be recreated (exports, renders, screenshots); see the module docs.
+/// Anything that can't be made again goes through [`write_atomic`].
+pub fn write_atomic_nosync(path: &Path, data: &[u8]) -> io::Result<()> {
+    replace_with(path, false, &mut |w| w.write_all(data)).map(|_| ())
+}
+
+/// Temp file (synced when `sync`) renamed over `path`, then the folder synced when `sync`.
+fn replace_with(path: &Path, sync: bool, fill: &mut dyn FnMut(&mut dyn Write) -> io::Result<()>) -> io::Result<u64> {
+    let (tmp, n) = write_temp(path, sync, fill)?;
    if let Err(e) = fs::rename(&tmp, path) {
        let _ = fs::remove_file(&tmp);
        return Err(e);
    }
-    sync_dir(parent_of(path));
+    if sync {
+        sync_dir(parent_of(path));
+    }
    Ok(n)
 }

@@ -155,8 +196,11 @@ pub fn write_new_unique(candidates: &mut dyn Iterator<Item = PathBuf>, data: &[u
    let Some(first) = candidates.peek().cloned() else {
        return Err(io::Error::new(io::ErrorKind::InvalidInput, "no file name to write"));
    };
-    let (tmp, _) = write_temp(&first, &mut |w| w.write_all(data))?;
+    let (tmp, _) = write_temp(&first, true, &mut |w| w.write_all(data))?;
    let r = (|| {
+        // Kept (issue #134 point 4): these files replace raws (Convert / Copy as DNG) or become
+        // library photos (merges). On a local disk the read usually comes from the cache, but on a
+        // network volume it can go back to the server, and next to encoding a DNG it costs little.
        if !same_content(&tmp, data)? {
            return Err(io::Error::other("the written file reads back different (failing drive or connection?)"));
        }
@@ -287,6 +331,33 @@ mod tests {
        let _ = fs::remove_dir_all(&d);
    }

+    #[test]
+    fn recreatable_outputs_are_atomic_without_a_sync() {
+        let d = temp("nosync");
+        let p = d.join("export.jpg");
+        let before = syncs_on_this_thread();
+        write_atomic_nosync(&p, b"one").unwrap();
+        write_atomic_nosync(&p, b"two two").unwrap();
+        assert_eq!(syncs_on_this_thread(), before, "no file or folder sync");
+        assert_eq!(fs::read(&p).unwrap(), b"two two");
+        assert_eq!(names(&d), vec!["export.jpg"], "no temp file left");
+        // still atomic: a failure part-way leaves the previous file and no temp file
+        {
+            let _f = fail_writes_after(3);
+            assert!(write_atomic_nosync(&p, &[9u8; 10_000]).is_err());
+        }
+        assert_eq!(fs::read(&p).unwrap(), b"two two");
+        assert_eq!(names(&d), vec!["export.jpg"]);
+        // the durable writers do sync (the file; the folder too where it can be opened)
+        let before = syncs_on_this_thread();
+        write_atomic(&p, b"three").unwrap();
+        let mid = syncs_on_this_thread();
+        assert!(mid > before);
+        write_new(&d.join("new.dng"), b"dng").unwrap();
+        assert!(syncs_on_this_thread() > mid);
+        let _ = fs::remove_dir_all(&d);
+    }
+
    #[test]
    fn new_files_never_replace_anything() {
        let d = temp("new");
@@ -297,3 +297,152 @@ fn folder_identity_ignores_spelling() {
    assert!(folder_within("/a/b", "/"));
    assert!(folder_within("C:\\x", "c:\\"));
 }
+
+/// People come from named *face* regions: counted once per photo, case-insensitive, most photos
+/// first; pets and unnamed faces are not people; the `person` filter and `person:` token match.
+#[test]
+fn people_from_named_face_regions() {
+    use lightcraft_meta::{Rect, Region, RegionKind};
+    let region = |name: Option<&str>, kind: RegionKind| Region {
+        rect: Rect { x0: 0.4, y0: 0.4, x1: 0.6, y1: 0.6 },
+        kind,
+        name: name.map(str::to_string),
+        description: None,
+    };
+    let mut c = Catalog::new();
+    let mut add = |name: &str, regions: Vec<Region>| {
+        let id = c.alloc_photo_id();
+        let mut p = Photo::new(id, Source::Demo { scene: 1 }, name, "JPEG", 6000, 4000, "2026-09-30T10:00:00");
+        p.meta.regions = regions;
+        c.apply(Op::AddPhoto { photo: Box::new(p) }).unwrap();
+        id
+    };
+    let a = add(
+        "a.jpg",
+        vec![region(Some("Jane Doe"), RegionKind::Face), region(Some("jane doe"), RegionKind::Face), region(Some("Rex"), RegionKind::Pet)],
+    );
+    let b =
+        add("b.jpg", vec![region(Some("JANE DOE"), RegionKind::Face), region(Some("John Roe"), RegionKind::Face), region(None, RegionKind::Face)]);
+    let big = Rect { x0: 0.2, y0: 0.2, x1: 0.8, y1: 0.8 };
+    let d = add("d.jpg", vec![Region { rect: big, ..region(Some("John Roe"), RegionKind::Face) }]);
+    let e = add("e.jpg", vec![region(Some("Sam"), RegionKind::Face)]);
+    add("f.jpg", vec![]);
+    let people = c.people();
+    let summary: Vec<(&str, usize)> = people.iter().map(|p| (p.name.as_str(), p.count)).collect();
+    assert_eq!(summary, vec![("Jane Doe", 2), ("John Roe", 2), ("Sam", 1)], "once per photo, pets and unnamed faces left out");
+    // the picture is the person's largest face; ties go to the lower photo id
+    assert_eq!((people[0].photo, people[0].face), (a, Rect { x0: 0.4, y0: 0.4, x1: 0.6, y1: 0.6 }));
+    assert_eq!((people[1].photo, people[1].face), (d, big), "the larger face wins over an earlier, smaller one");
+
+    let q = |f: Filter| c.query(&f, &Sort::default());
+    assert_eq!(q(Filter { person: Some("jane doe".into()), ..Default::default() }).len(), 2);
+    let mut got = q(Filter { person: Some("John Roe".into()), ..Default::default() });
+    got.sort();
+    assert_eq!(got, vec![b, d]);
+    assert!(q(Filter { person: Some("Rex".into()), ..Default::default() }).is_empty(), "a pet is not a person");
+    assert_eq!(q(Filter { text: "person:SAM".into(), ..Default::default() }), vec![e], "the search token finds a person, any case");
+    assert!(q(Filter { person: Some("Jane Doe".into()), ..Default::default() }).contains(&a));
+
+    // other filters narrow who is offered (so picking a person never ends in an empty grid); the
+    // `person` filter itself does not
+    c.apply(Op::SetRating { id: b, rating: 3 }).unwrap();
+    let names = |f: Filter| c.people_in(&f).into_iter().map(|p| (p.name, p.count)).collect::<Vec<_>>();
+    let rated = Filter { rating: 1, ..Default::default() };
+    assert_eq!(
+        names(rated.clone()),
+        vec![("JANE DOE".to_string(), 1), ("John Roe".to_string(), 1)],
+        "only the rated photo's people, counted within it, spelled as first seen there"
+    );
+    assert_eq!(
+        names(Filter { person: Some("Sam".into()), ..rated }),
+        names(Filter { rating: 1, ..Default::default() }),
+        "the person filter is ignored"
+    );
+    assert_eq!(names(Filter { rating: 5, ..Default::default() }), vec![], "nobody in the filtered photos");
+}
+
+/// Most photos have no regions: the field is left out of the catalog JSON then, and a catalog written
+/// before regions existed (no `regions` key) reads with none.
+#[test]
+fn empty_regions_are_not_serialized_and_default_when_missing() {
+    let m = Meta { keywords: vec!["k".into()], ..Default::default() };
+    let v = serde_json::to_value(&m).unwrap();
+    assert!(v.get("regions").is_none(), "{v}");
+    let back: Meta = serde_json::from_value(v).unwrap();
+    assert!(back.regions.is_empty());
+    let mut with = m.clone();
+    with.regions.push(lightcraft_meta::Region {
+        rect: lightcraft_meta::Rect { x0: 0.1, y0: 0.1, x1: 0.2, y1: 0.2 },
+        kind: lightcraft_meta::RegionKind::Face,
+        name: Some("A".into()),
+        description: None,
+    });
+    let back: Meta = serde_json::from_str(&serde_json::to_string(&with).unwrap()).unwrap();
+    assert_eq!(back, with);
+}
+
+// ---- random sort: Given a seed, the order is a stable, reproducible shuffle of the matching photos
+
+fn many(c: &mut Catalog, n: usize) -> Vec<PhotoId> {
+    (0..n).map(|i| photo(c, &format!("p{i:03}.jpg"), &format!("2026-04-{:02}T10:00:00", i % 28 + 1))).collect()
+}
+
+fn random(seed: u64) -> Sort {
+    Sort { key: SortKey::Random, seed, ..Default::default() }
+}
+
+#[test]
+fn random_sort_is_a_reproducible_permutation() {
+    let mut c = Catalog::new();
+    let ids = many(&mut c, 50);
+    let a = c.query(&Filter::default(), &random(7));
+    assert_eq!(a, c.query(&Filter::default(), &random(7)), "same seed, same order");
+    let mut sorted = a.clone();
+    sorted.sort();
+    let mut all = ids.clone();
+    all.sort();
+    assert_eq!(sorted, all, "every photo exactly once");
+    assert_ne!(a, c.query(&Filter::default(), &random(8)), "another seed, another order");
+    assert_ne!(a, c.query(&Filter::default(), &Sort::default()), "not just the date order");
+}
+
+#[test]
+fn random_sort_keeps_the_relative_order_when_the_set_changes() {
+    let mut c = Catalog::new();
+    let ids = many(&mut c, 30);
+    let before = c.query(&Filter::default(), &random(3));
+    let added = photo(&mut c, "new.jpg", "2026-05-01T10:00:00");
+    c.apply(Op::SetRating { id: ids[0], rating: 5 }).unwrap();
+    let after: Vec<PhotoId> = c.query(&Filter::default(), &random(3)).into_iter().filter(|id| *id != added).collect();
+    assert_eq!(after, before, "adding a photo or editing metadata must not reshuffle the others");
+}
+
+#[test]
+fn random_sort_respects_the_filter_and_handles_tiny_sets() {
+    let mut c = Catalog::new();
+    assert!(c.query(&Filter::default(), &random(1)).is_empty());
+    let ids = many(&mut c, 10);
+    c.apply(Op::SetRating { id: ids[4], rating: 5 }).unwrap();
+    assert_eq!(c.query(&Filter { rating: 5, ..Default::default() }, &random(1)), vec![ids[4]]);
+}
+
+#[test]
+fn random_sort_direction_reverses_and_serde_defaults_hold() {
+    let mut c = Catalog::new();
+    many(&mut c, 20);
+    let desc = c.query(&Filter::default(), &Sort { ascending: false, ..random(5) });
+    let mut asc = c.query(&Filter::default(), &Sort { ascending: true, ..random(5) });
+    asc.reverse();
+    assert_eq!(desc, asc);
+    // saved sorts from before the seed existed still load
+    let old: Sort = serde_json::from_str(r#"{"key":"fileName","ascending":true}"#).unwrap();
+    assert_eq!(old.seed, 0);
+    assert_eq!(serde_json::from_str::<Sort>(r#"{"key":"random","seed":9}"#).unwrap(), Sort { key: SortKey::Random, seed: 9, ..Default::default() });
+}
+
+#[test]
+fn random_sort_has_no_date_headers() {
+    let mut c = Catalog::new();
+    let ids = many(&mut c, 5);
+    assert!(c.date_runs(&ids, SortKey::Random, GroupBy::Day).is_empty());
+}
@@ -0,0 +1,404 @@
+//! The library's folder tree: where the imported photos live on disk (see [`crate::folders`]).
+//!
+//! Scenarios, in the words of someone browsing their library:
+//!
+//! * Given photos imported from several folders, the tree lists those folders and no others,
+//!   each with how many photos it holds, under the disk (volume) they are on.
+//! * A folder's count includes the folders inside it.
+//! * Every folder is a row of its own, the ones above the imported photos included.
+//! * Photos only browsed in Local, deleted photos and demo scenes are not "imported from" anywhere.
+//! * However a folder is spelled, it is one folder.
+//! * Choosing a folder shows what was imported from it and from the folders inside it — exactly
+//!   as many photos as the row says.
+
+use crate::*;
+
+fn add(c: &mut Catalog, path: &str) -> PhotoId {
+    add_with(c, path, |_| {})
+}
+
+fn add_with(c: &mut Catalog, path: &str, tweak: impl FnOnce(&mut Photo)) -> PhotoId {
+    let id = c.alloc_photo_id();
+    let name = path.rsplit(['/', '\\']).next().unwrap_or(path);
+    let mut p = Photo::new(id, Source::File { path: path.into() }, name, "JPEG", 60, 40, "2026-01-01T10:00:00");
+    tweak(&mut p);
+    c.apply(Op::AddPhoto { photo: Box::new(p) }).unwrap();
+    id
+}
+
+fn library(paths: &[&str]) -> Catalog {
+    let mut c = Catalog::new();
+    paths.iter().for_each(|p| {
+        add(&mut c, p);
+    });
+    c
+}
+
+/// `(name, count, own)` of each node, depth first.
+fn outline(nodes: &[FolderNode]) -> Vec<(String, usize, usize)> {
+    fn walk(n: &FolderNode, out: &mut Vec<(String, usize, usize)>) {
+        out.push((n.name.clone(), n.count, n.own));
+        n.children.iter().for_each(|c| walk(c, out));
+    }
+    let mut out = Vec::new();
+    nodes.iter().for_each(|n| walk(n, &mut out));
+    out
+}
+
+fn row(name: &str, count: usize, own: usize) -> (String, usize, usize) {
+    (name.to_string(), count, own)
+}
+
+fn rows(paths: &[&str]) -> Vec<(String, usize, usize)> {
+    outline(&library(paths).folder_tree())
+}
+
+#[test]
+fn an_empty_library_has_no_folders() {
+    assert!(Catalog::new().folder_tree().is_empty());
+}
+
+#[test]
+fn only_folders_with_imported_photos_are_listed_with_their_counts() {
+    let c = library(&["/pics/trip/a.jpg", "/pics/trip/b.jpg", "/pics/home/c.jpg"]);
+    let tree = c.folder_tree();
+    assert_eq!(outline(&tree), vec![row("/", 3, 0), row("pics", 3, 0), row("home", 1, 1), row("trip", 2, 2)]);
+    assert!(tree[0].volume && !tree[0].children[0].volume);
+    assert_eq!(tree[0].children[0].children[1].path, "/pics/trip", "a row knows its folder, for choosing it");
+}
+
+#[test]
+fn a_folders_count_includes_the_folders_inside_it() {
+    let r = rows(&["/pics/trip/a.jpg", "/pics/trip/day1/b.jpg", "/pics/trip/day1/c.jpg", "/pics/trip/day2/d.jpg"]);
+    assert_eq!(r, vec![row("/", 4, 0), row("pics", 4, 0), row("trip", 4, 1), row("day1", 2, 2), row("day2", 1, 1)]);
+}
+
+#[test]
+fn every_folder_is_a_row_of_its_own_even_when_it_holds_nothing_itself() {
+    let c = library(&["/Users/me/Pictures/2024/a.jpg", "/Users/me/Pictures/2025/b.jpg", "/Volumes/nas/photos/c.jpg"]);
+    let tree = c.folder_tree();
+    assert_eq!(
+        outline(&tree),
+        vec![
+            row("/", 2, 0),
+            row("Users", 2, 0),
+            row("me", 2, 0),
+            row("Pictures", 2, 0),
+            row("2024", 1, 1),
+            row("2025", 1, 1),
+            row("nas", 1, 0),
+            row("photos", 1, 1)
+        ]
+    );
+    assert_eq!(tree[0].children[0].children[0].children[0].path, "/Users/me/Pictures", "a row is exactly the folder it names");
+}
+
+#[test]
+fn a_folder_with_photos_of_its_own_is_not_folded_into_its_child() {
+    assert_eq!(rows(&["/pics/a.jpg", "/pics/trip/b.jpg"]), vec![row("/", 2, 0), row("pics", 2, 1), row("trip", 1, 1)]);
+}
+
+#[test]
+fn browsed_deleted_and_demo_photos_are_not_imported_from_anywhere() {
+    let mut c = Catalog::new();
+    add(&mut c, "/pics/kept/a.jpg");
+    add_with(&mut c, "/pics/browsed/b.jpg", |p| p.local = true);
+    add_with(&mut c, "/pics/gone/c.jpg", |p| p.deleted = true);
+    let id = c.alloc_photo_id();
+    let demo = Photo::new(id, Source::Demo { scene: 1 }, "demo", "JPEG", 60, 40, "2026-01-01T10:00:00");
+    c.apply(Op::AddPhoto { photo: Box::new(demo) }).unwrap();
+    assert_eq!(outline(&c.folder_tree()), vec![row("/", 1, 0), row("pics", 1, 0), row("kept", 1, 1)]);
+}
+
+#[test]
+fn however_a_folder_is_spelled_it_is_one_folder() {
+    let r = rows(&["/pics/trip/a.jpg", "/pics//trip/./b.jpg", "/pics\\trip\\c.jpg", "/pics/x/../trip/d.jpg"]);
+    assert_eq!(r, vec![row("/", 4, 0), row("pics", 4, 0), row("trip", 4, 4)]);
+}
+
+#[test]
+fn each_disk_is_a_volume_of_its_own() {
+    // macOS, Linux and Windows habits for where disks appear
+    let r = rows(&["/Volumes/nas/p/1.jpg", "/media/me/usb/2.jpg", "/run/media/me/card/3.jpg", "/mnt/disk/4.jpg"]);
+    assert_eq!(r, vec![row("card", 1, 1), row("disk", 1, 1), row("nas", 1, 0), row("p", 1, 1), row("usb", 1, 1)]);
+    let r = rows(&["D:\\Photos\\2024\\a.jpg", "D:\\Photos\\2025\\b.jpg", "C:\\x\\c.jpg"]);
+    assert_eq!(r, vec![row("C:", 1, 0), row("x", 1, 1), row("D:", 2, 0), row("Photos", 2, 0), row("2024", 1, 1), row("2025", 1, 1)]);
+}
+
+#[test]
+fn a_network_share_is_a_volume_and_two_spellings_are_one() {
+    let r = rows(&["\\\\srv\\s1\\a\\1.jpg", "\\\\srv\\s2\\b\\2.jpg"]);
+    assert_eq!(r, vec![row("//srv/s1", 1, 0), row("a", 1, 1), row("//srv/s2", 1, 0), row("b", 1, 1)]);
+    // the verbatim form Windows APIs give is the same share
+    let r = rows(&["\\\\?\\UNC\\srv\\s1\\a\\1.jpg", "\\\\srv\\s1\\a\\2.jpg"]);
+    assert_eq!(r, vec![row("//srv/s1", 2, 0), row("a", 2, 2)]);
+}
+
+#[test]
+fn a_samba_share_mounted_on_a_mac_is_a_volume_named_after_the_share() {
+    // Finder mounts every share under /Volumes, and a second mount of the same share gets a suffix
+    let r = rows(&["/Volumes/tokyo/Photos/2024/a.jpg", "/Volumes/tokyo/Photos/2025/b.jpg", "/Volumes/tokyo-1/old/c.jpg", "/Volumes/東京 NAS/d.jpg"]);
+    assert_eq!(
+        r,
+        vec![
+            row("tokyo", 2, 0),
+            row("Photos", 2, 0),
+            row("2024", 1, 1),
+            row("2025", 1, 1),
+            row("tokyo-1", 1, 0),
+            row("old", 1, 1),
+            row("東京 NAS", 1, 1)
+        ]
+    );
+    let tree = library(&["/Volumes/tokyo/Photos/a.jpg"]).folder_tree();
+    assert_eq!((tree[0].path.as_str(), tree[0].volume), ("/Volumes/tokyo", true), "choosing the share shows everything on it");
+}
+
+#[test]
+fn shares_the_other_systems_mount_are_volumes_too() {
+    // Linux desktops: gvfs mounts per user, with the server and share in the mount's name
+    let gvfs = "/run/user/1000/gvfs/smb-share:server=tokyo,share=photos";
+    let r = rows(&[&format!("{gvfs}/2024/a.jpg"), "/run/user/1000/gvfs/sftp:host=nas/b.jpg"]);
+    assert_eq!(r, vec![row("photos on tokyo", 1, 0), row("2024", 1, 1), row("sftp:host=nas", 1, 1)]);
+    // NFS automounts: Linux /net/<host>, macOS /Network/Servers/<host>
+    let r = rows(&["/net/tokyo/export/a.jpg", "/Network/Servers/osaka/vol/b.jpg"]);
+    assert_eq!(r, vec![row("osaka", 1, 0), row("vol", 1, 1), row("tokyo", 1, 0), row("export", 1, 1)]);
+    // Windows: a share by name or by address, the WSL file system, a mapped drive
+    let r = rows(&[r"\\tokyo.local\photos\a.jpg", r"\\192.168.1.5\scans\b.jpg", r"\\wsl$\Ubuntu\home\me\c.jpg", r"Z:\d.jpg"]);
+    assert_eq!(
+        r,
+        vec![
+            row("//192.168.1.5/scans", 1, 1),
+            row("//tokyo.local/photos", 1, 1),
+            row("//wsl$/Ubuntu", 1, 0),
+            row("home", 1, 0),
+            row("me", 1, 1),
+            row("Z:", 1, 1)
+        ]
+    );
+}
+
+#[test]
+fn a_share_that_is_not_mounted_costs_nothing() {
+    // the tree is made from the catalog's own records: it never looks at a disk, so a share that
+    // is asleep or gone lists (and counts) exactly like one that is there
+    let c = library(&["/Volumes/definitely-not-mounted/a/b.jpg", r"\\unreachable.invalid\share\c.jpg"]);
+    let tree = c.folder_tree();
+    assert_eq!(tree.iter().map(|n| n.count).sum::<usize>(), 2);
+}
+
+#[test]
+fn a_photo_in_the_root_of_a_disk_counts_for_the_disk() {
+    assert_eq!(rows(&["/x.jpg", "/d/y.jpg"]), vec![row("/", 2, 1), row("d", 1, 1)]);
+    assert_eq!(rows(&["C:\\x.jpg"]), vec![row("C:", 1, 1)]);
+}
+
+#[test]
+fn photos_with_no_folder_are_left_out() {
+    assert!(rows(&["x.jpg", ""]).is_empty());
+}
+
+#[test]
+fn folders_are_listed_by_name_ignoring_case() {
+    let names: Vec<String> = rows(&["/p/b/1.jpg", "/p/A/2.jpg", "/p/c/3.jpg"]).into_iter().skip(2).map(|r| r.0).collect();
+    assert_eq!(names, ["A", "b", "c"]);
+}
+
+#[test]
+fn absurdly_deep_paths_neither_crash_nor_lose_photos() {
+    let deep = format!("/{}/a.jpg", vec!["d"; 5000].join("/"));
+    let tree = library(&[&deep]).folder_tree();
+    assert_eq!(tree.iter().map(|n| n.count).sum::<usize>(), 1);
+    assert!(outline(&tree).len() <= crate::folders::MAX_DEPTH + 2);
+}
+
+#[test]
+fn choosing_a_folder_shows_what_was_imported_from_it_and_below() {
+    let mut c = Catalog::new();
+    let trip = add(&mut c, "/pics/trip/a.jpg");
+    let day = add(&mut c, "/pics/trip/day1/b.jpg");
+    let sibling = add(&mut c, "/pics/trip2/c.jpg"); // shares the name's start, not the folder
+    let browsed = add_with(&mut c, "/pics/trip/d.jpg", |p| p.local = true);
+    let f = Filter { library_folder: Some("/pics//trip/".into()), ..Default::default() };
+    let shown = |id: PhotoId| f.matches(c.photo(id).unwrap(), &c);
+    assert!(shown(trip) && shown(day));
+    assert!(!shown(sibling), "/pics/trip2 is another folder");
+    assert!(!shown(browsed), "browsed photos are not part of the library's folders");
+    assert_eq!(f.describe(), "folder /pics//trip/");
+}
+
+#[test]
+fn recently_deleted_shows_the_deleted_photos_of_the_chosen_folder() {
+    let mut c = Catalog::new();
+    let gone = add_with(&mut c, "/pics/trip/a.jpg", |p| p.deleted = true);
+    let kept = add(&mut c, "/pics/trip/b.jpg");
+    let f = Filter { library_folder: Some("/pics/trip".into()), deleted: true, ..Default::default() };
+    assert!(f.matches(c.photo(gone).unwrap(), &c));
+    assert!(!f.matches(c.photo(kept).unwrap(), &c));
+}
+
+#[test]
+fn an_empty_folder_choice_is_no_choice() {
+    let c = library(&["/pics/a.jpg"]);
+    let f = Filter { library_folder: Some("  ".into()), ..Default::default() };
+    assert_eq!(c.query(&f, &Sort::default()).len(), 1);
+}
+
+#[test]
+fn every_row_shows_exactly_as_many_photos_as_it_says() {
+    let c = library(&[
+        "/Users/me/Pictures/2024/a.jpg",
+        "/Users/me/Pictures/2024/b.jpg",
+        "/Users/me/Pictures/2025/c.jpg",
+        "/Users/me/Pictures/d.jpg",
+        "/Volumes/nas/photos/e.jpg",
+        "/Volumes/nas/f.jpg",
+        "/x.jpg",
+        "/a/../b/g.jpg",
+        "D:\\Photos\\2024\\h.jpg",
+        "d:/Photos/i.jpg",
+        "\\\\srv\\s1\\a\\j.jpg",
+        "\\\\?\\UNC\\srv\\s2\\k.jpg",
+        "/pics/trip/l.jpg",
+        "/pics/trip2/m.jpg",
+        "/Volumes/tokyo/Photos/2024/n.jpg",
+        "/Volumes/tokyo/o.jpg",
+        "/run/user/1000/gvfs/smb-share:server=tokyo,share=photos/p.jpg",
+        "/net/osaka/export/q.jpg",
+        r"\\wsl$\Ubuntu\home\me\r.jpg",
+        // odd spellings the tree and the filter must read the same way
+        "//server/share/../other/1.jpg",
+        "//server/share/ok/2.jpg",
+        "//a b//A/f.jpg",
+        r"\\wsl$\Ubuntu\..\a\1.jpg",
+        // a folder that holds other disks as well as photos of its own
+        "/Volumes/1.jpg",
+        "/mnt/2.jpg",
+        "/mnt/disk/3.jpg",
+    ]);
+    fn check(c: &Catalog, nodes: &[FolderNode], seen: &mut usize) {
+        for n in nodes {
+            // the startup volume's row only opens: its path "/" would cover every other disk
+            if n.selectable {
+                let f = Filter { library_folder: Some(n.path.clone()), ..Default::default() };
+                assert_eq!(c.query(&f, &Sort::default()).len(), n.count, "{} ({})", n.name, n.path);
+                *seen += 1;
+            }
+            check(c, &n.children, seen);
+        }
+    }
+    let mut seen = 0;
+    check(&c, &c.folder_tree(), &mut seen);
+    assert!(seen > 10, "{seen} rows checked");
+}
+
+fn find<'a>(nodes: &'a [FolderNode], path: &str) -> Option<&'a FolderNode> {
+    nodes.iter().find_map(|n| if n.path == path { Some(n) } else { find(&n.children, path) })
+}
+
+#[test]
+fn a_row_that_would_cover_other_disks_is_not_offered_for_choosing() {
+    let tree = library(&["/Users/me/a.jpg", "/Volumes/1.jpg", "/Volumes/tokyo/x.jpg", "/mnt/2.jpg"]).folder_tree();
+    let sel = |p: &str| find(&tree, p).map(|n| n.selectable);
+    assert_eq!(sel("/"), Some(false), "the startup disk's path covers every disk");
+    assert_eq!(sel("/Volumes"), Some(false), "it holds the tokyo disk");
+    assert_eq!(sel("/Volumes/tokyo"), Some(true));
+    assert_eq!(sel("/Users/me"), Some(true));
+    assert_eq!(sel("/mnt"), Some(true), "no disk is mounted below it in this library");
+}
+
+#[test]
+fn the_tree_and_the_filter_read_odd_spellings_the_same_way() {
+    // `..` cannot climb above a share, and repeated separators between server and share are one
+    let tree = library(&["//server/share/../other/1.jpg", "//a b//A/f.jpg"]).folder_tree();
+    assert_eq!(outline(&tree), vec![row("//a b/A", 1, 1), row("//server/share", 1, 0), row("other", 1, 1)]);
+}
+
+#[test]
+fn a_path_that_names_no_folder_chooses_nothing() {
+    let c = library(&["/pics/a.jpg", "C:\\b\\c.jpg"]);
+    for dot in [".", "./", "a/..", "../.."] {
+        let f = Filter { library_folder: Some(dot.into()), ..Default::default() };
+        assert_eq!(c.query(&f, &Sort::default()).len(), 0, "{dot:?} is no folder, not everything");
+    }
+}
+
+#[test]
+fn a_folder_is_labelled_by_its_last_two_names() {
+    use crate::folders::folder_label;
+    assert_eq!(folder_label("/Volumes/tokyo/photos/travel"), "photos/travel");
+    assert_eq!(folder_label("/Volumes/tokyo/"), "Volumes/tokyo");
+    assert_eq!(folder_label(r"C:\Photos\2024"), "Photos/2024");
+    assert_eq!(folder_label("/"), "/");
+    assert_eq!(folder_label(""), "");
+}
+
+#[test]
+fn disk_roots_are_told_from_folders() {
+    use crate::folders::{is_disk_root, is_startup_disk};
+    for p in ["/", "C:", "C:\\", r"\\?\C:\", r"\\srv\share", "/Volumes/nas", "/mnt/disk", "/net/host"] {
+        assert!(is_disk_root(p), "{p}");
+    }
+    for p in ["/Volumes", "/Users", "C:\\Photos", r"\\srv\share\x", "/Volumes/nas/p", "."] {
+        assert!(!is_disk_root(p), "{p}");
+    }
+    assert!(is_startup_disk("/") && is_startup_disk("//") && !is_startup_disk("/Volumes/nas") && !is_startup_disk("C:"));
+}
+
+#[test]
+fn a_folder_name_with_spaces_at_its_edge_is_its_own_folder() {
+    // legal on macOS and Linux: `/p/shoot ` is not `/p/shoot`
+    let c = library(&["/p/shoot /a.jpg", "/p/shoot/b.jpg", "/p/other/c.jpg"]);
+    let tree = c.folder_tree();
+    let shoot_space = find(&tree, "/p/shoot ").expect("its own row");
+    let shoot = find(&tree, "/p/shoot").expect("and the other");
+    for (node, want) in [(shoot_space, "a.jpg"), (shoot, "b.jpg")] {
+        let f = Filter { library_folder: Some(node.path.clone()), ..Default::default() };
+        let ids = c.query(&f, &Sort::default());
+        let names: Vec<&str> = ids.iter().filter_map(|id| c.photo(*id)).map(|p| p.file_name.as_str()).collect();
+        assert_eq!(names, [want], "{:?} shows its own photo", node.path);
+    }
+}
+
+#[test]
+fn a_local_photo_never_counts_as_imported_even_when_a_disk_folder_is_also_shown() {
+    let mut c = Catalog::new();
+    let browsed = add_with(&mut c, "/pics/trip/b.jpg", |p| p.local = true);
+    let f = Filter { folder: Some("/pics/trip".into()), library_folder: Some("/pics/trip".into()), ..Default::default() };
+    assert!(!f.matches(c.photo(browsed).unwrap(), &c));
+}
+
+#[test]
+fn the_quick_check_agrees_with_the_careful_one() {
+    use crate::query::{folder_key, key_within, photo_in_root};
+    let paths = [
+        "/a/b/c.jpg",
+        "/a/b/d/e.jpg",
+        "/a/bc/x.jpg",
+        "/a/./b/x.jpg",
+        "/a/../a/b/x.jpg",
+        "/a//b/x.jpg",
+        "/a\\b\\x.jpg",
+        "/a/b ",
+        "/a/b /x.jpg",
+        "/.hidden/x.jpg",
+        "/a/.b/x.jpg",
+        "/x.jpg",
+        "//srv/share/x.jpg",
+        "C:\\a\\b\\x.jpg",
+        "relative/a/b/x.jpg",
+        "/Volumes/tokyo/a/x.jpg",
+        "/日本/写真/x.jpg",
+    ];
+    let roots = ["/", "/a", "/a/b", "/a/b/", "/a/bc", "/a/b ", "/Volumes/tokyo", "//srv/share", "C:\\a", "/日本", "relative", "/a/../a/b"];
+    for p in paths {
+        let mut c = Catalog::new();
+        let id = add(&mut c, p);
+        let photo = c.photo(id).unwrap();
+        for r in roots {
+            let root = folder_key(r);
+            let slow = crate::local::folder_of(photo).is_some_and(|f| key_within(&f, &root));
+            assert_eq!(photo_in_root(photo, &root), slow, "{p:?} in {r:?}");
+        }
+    }
+}
@@ -24,6 +24,12 @@ encode_webp_lossless(&img, &meta)?;
 encode_avif(&img, 70, 6, &meta)?;                        // native + feature `avif`
 ```

+Thumbnail fallback decoding limits the source to 64 million pixels by default.
+Non-JPEG decoders allocate at source resolution before resizing, even for a tiny
+thumbnail. Use `decode_thumbnail_with` and `ThumbnailOptions::max_pixels` to set
+a different source budget. Oversized sources return `Error::TooLarge`; embedded
+JPEG previews can still be used without decoding the full source image.
+
 `Format::RawTiffLike` (DNG, CR2, NEF, ARW, PEF, ORF, RW2, SRW, …) and `Format::RawOther` (CR3, RAF,
 CRW, MRW, X3F) are detected so the engine can route them to `lightcraft-raw`; `decode` returns
 `Error::Unsupported` for them.
@@ -50,6 +56,10 @@ or CMYK profile converted by the CMS straight to linear Rec.2020), `Container` (
 EXIF `R03` Adobe RGB hint), `Untagged` (assumed sRGB; untagged float data assumed linear),
 `IccUnsupported` (profile present but unusable → **sRGB fallback**), `Naive` (CMYK without profile).

+`decode_jpeg_with_fallback(bytes, opts, space)` lets an enclosing RAW container supply the colour
+space of a JPEG with no ICC or EXIF metadata. It applies the transfer curve before linear-light
+resizing; a JPEG carrying its own metadata retains its existing interpretation.
+
 ICC profiles are parsed with `moxcms` (v2/v4, `curv`/`para` TRCs, `chad`); sRGB, Display P3,
 Adobe RGB (1998), ProPhoto (ROMM) and Rec.2020 are recognised by colorants. `icc::write_matrix_trc`
 emits v4 display profiles (D50 PCS, Bradford `chad`) for export embedding.
@@ -146,7 +146,19 @@ pub fn write_matrix_trc(space: &RgbSpace, trc: &Trc) -> Vec<u8> {
    };
    p.description = Some(ProfileText::Localizable(vec![LocalizableString::new("en".into(), "US".into(), desc)]));
    p.copyright = Some(ProfileText::Localizable(vec![LocalizableString::new("en".into(), "US".into(), "No copyright, use freely".into())]));
-    align_tags(&p.encode().unwrap_or_default())
+    align_tags(&fixed_date(p.encode().unwrap_or_default()))
+}
+
+/// Zero the header's creation date/time (ICC.1 §7.2.8, bytes 24..36) so a profile's bytes depend
+/// only on its colour space and curve. `moxcms` stamps the wall clock there on every `encode`
+/// (ignoring `ColorProfile::creation_date_time`), which made two exports of one photo differ in
+/// the embedded profile and nowhere else, so output hashes could not be compared (#180). Readers
+/// do not interpret the field; all zeros is the conventional "unspecified" value.
+fn fixed_date(mut b: Vec<u8>) -> Vec<u8> {
+    if let Some(date) = b.get_mut(24..36) {
+        date.fill(0);
+    }
+    b
 }

 /// Re-lay a profile's tag data on 4-byte boundaries (ICC.1 §7.3.1). The encoder packs tags back to
@@ -300,6 +312,23 @@ mod tests {
        let _ = SRGB;
    }

+    /// Two profiles for one space are byte-identical, and the header date is fixed: exports of the
+    /// same photo with the same settings hash the same (#180).
+    #[test]
+    fn written_profiles_are_deterministic() {
+        for n in NamedSpace::ALL {
+            let a = write_named(n);
+            let b = write_named(n);
+            assert_eq!(a, b, "{n:?}");
+            assert_eq!(&a[24..36], &[0u8; 12], "{n:?} header date/time");
+            // the profile ID is "not computed", not a hash of a timestamp
+            assert_eq!(&a[84..100], &[0u8; 16], "{n:?} profile ID");
+        }
+        let lin = write_matrix_trc(&PROPHOTO, &Trc::Linear);
+        assert_eq!(lin, write_matrix_trc(&PROPHOTO, &Trc::Linear));
+        assert_eq!(&lin[24..36], &[0u8; 12]);
+    }
+
    #[test]
    fn garbage_is_none() {
        assert!(parse(&[]).is_none());
@@ -105,6 +105,10 @@ pub(crate) fn parse_markers(b: &[u8]) -> Option<Markers> {
 }

 pub(crate) fn decode(bytes: &[u8], opts: &DecodeOptions) -> Result<Decoded> {
+    decode_with_fallback(bytes, opts, None)
+}
+
+pub(crate) fn decode_with_fallback(bytes: &[u8], opts: &DecodeOptions, fallback: Option<crate::NamedSpace>) -> Result<Decoded> {
    let m = parse_markers(bytes).ok_or_else(|| Error::Malformed(F, "missing SOI".into()))?;
    if m.components == 0 {
        return Err(Error::Malformed(F, "no frame header".into()));
@@ -119,7 +123,10 @@ pub(crate) fn decode(bytes: &[u8], opts: &DecodeOptions) -> Result<Decoded> {
    } else {
        decode_zune(bytes, &m)?
    };
-    let meta = Meta { icc: m.icc, exif: m.exif, xmp: m.xmp, ..Default::default() };
+    // A raw container may carry the colour declaration of an otherwise untagged preview.
+    // Apply it before linearization/resizing; existing JPEG metadata always wins.
+    let hint = fallback.filter(|_| m.icc.is_none() && m.exif.is_none()).map(|space| crate::SourceSpace::named(space, crate::SpaceOrigin::Container));
+    let meta = Meta { icc: m.icc, exif: m.exif, xmp: m.xmp, hint, ..Default::default() };
    finish(F, raw, meta, (m.width, m.height), opts)
 }

@@ -246,6 +253,44 @@ fn mpf_images(m: &Markers) -> Vec<(usize, usize)> {
 mod tests {
    use super::*;

+    #[test]
+    fn container_fallback_matches_tagged_jpeg_before_resizing_and_keeps_own_metadata() {
+        use crate::{ChromaSubsampling, EncodeImage, EncodeMeta, NamedSpace, Samples, SpaceOrigin, encode_jpeg};
+        let pixels: Vec<u8> = (0..16 * 16).flat_map(|i| if i % 2 == 0 { [120, 180, 90] } else { [30, 100, 200] }).collect();
+        let encode = |icc, exif| {
+            encode_jpeg(
+                &EncodeImage::new(16, 16, 3, Samples::U8(&pixels)),
+                100,
+                ChromaSubsampling::S444,
+                &EncodeMeta { icc, exif, ..Default::default() },
+            )
+            .unwrap()
+        };
+        let untagged = encode(None, None);
+        let adobe = crate::icc::write_named(NamedSpace::AdobeRgb);
+        let tagged = encode(Some(&adobe), None);
+        for opts in [DecodeOptions::default(), DecodeOptions::fit(3, 3)] {
+            let with = crate::decode_jpeg_with_fallback(&untagged, opts, NamedSpace::AdobeRgb).unwrap();
+            let expected = crate::decode(&tagged, opts).unwrap();
+            assert_eq!(with.space.origin, SpaceOrigin::Container);
+            let (a, b) = (with.to_working(), expected.to_working());
+            for (p, q) in a.data.iter().zip(&b.data) {
+                assert!(p.iter().zip(q).all(|(a, b)| (a - b).abs() < 0.0001), "{p:?} != {q:?}");
+            }
+        }
+        let srgb = crate::icc::write_named(NamedSpace::Srgb);
+        let exif = crate::exif::minimal_exif(6);
+        for bytes in [encode(Some(&srgb), None), encode(None, Some(&exif)), encode(Some(b"bad ICC"), None)] {
+            let opts = DecodeOptions::fit(5, 5);
+            let with = crate::decode_jpeg_with_fallback(&bytes, opts, NamedSpace::AdobeRgb).unwrap();
+            let expected = crate::decode(&bytes, opts).unwrap();
+            assert_eq!(with.space, expected.space);
+            assert_eq!(with.image, expected.image);
+            assert_eq!(with.orientation, expected.orientation);
+        }
+        assert!(crate::decode_jpeg_with_fallback(b"bad JPEG", DecodeOptions::default(), NamedSpace::AdobeRgb).is_err());
+    }
+
    #[test]
    fn scaled_request_covers() {
        assert_eq!(scaled_request(6000, 4000, 256, 256), (256, 171));
@@ -156,6 +156,14 @@ pub fn decode(bytes: &[u8], opts: DecodeOptions) -> Result<Decoded> {
    std::panic::catch_unwind(|| decode_unguarded(bytes, format, &opts)).unwrap_or_else(|_| Err(Error::Malformed(format, "decoder panicked".into())))
 }

+/// Decode a JPEG preview with its enclosing container's colour space as a fallback.
+/// A JPEG carrying ICC or EXIF metadata keeps its own interpretation. The fallback is applied
+/// before transfer decoding and linear-light resizing, never to already-resampled pixels.
+pub fn decode_jpeg_with_fallback(bytes: &[u8], opts: DecodeOptions, fallback: NamedSpace) -> Result<Decoded> {
+    std::panic::catch_unwind(|| jpeg::decode_with_fallback(bytes, &opts, Some(fallback)))
+        .unwrap_or_else(|_| Err(Error::Malformed(Format::Jpeg, "decoder panicked".into())))
+}
+
 /// [`decode`] without the panic guard (for fuzzing our own code paths).
 #[doc(hidden)]
 pub fn decode_unguarded(bytes: &[u8], format: Format, opts: &DecodeOptions) -> Result<Decoded> {
@@ -217,11 +225,19 @@ pub struct ThumbnailOptions {
    /// smaller size). Defaults to `max_edge`, i.e. only previews that need no upscaling. Lower it
    /// (e.g. 160 for typical EXIF thumbnails) for an instant placeholder.
    pub min_embedded_edge: u32,
+    /// Maximum source pixels for fallback decoding (default 64 MP). Non-JPEG formats
+    /// decode at source resolution before resizing, so output size does not bound memory.
+    #[serde(default = "thumbnail_max_pixels")]
+    pub max_pixels: u64,
+}
+
+fn thumbnail_max_pixels() -> u64 {
+    64_000_000
 }

 impl ThumbnailOptions {
    pub fn new(max_edge: u32) -> Self {
-        ThumbnailOptions { max_edge, min_embedded_edge: max_edge }
+        ThumbnailOptions { max_edge, min_embedded_edge: max_edge, max_pixels: thumbnail_max_pixels() }
    }
 }

@@ -240,7 +256,7 @@ pub fn decode_thumbnail_with(bytes: &[u8], opts: &ThumbnailOptions) -> Result<Th
    {
        return Ok(t);
    }
-    let d = decode(bytes, DecodeOptions::fit(max_edge, max_edge))?;
+    let d = decode(bytes, DecodeOptions { max_size: Some((max_edge, max_edge)), max_pixels: opts.max_pixels })?;
    Ok(Thumbnail {
        image: d.to_srgb8(),
        orientation: d.orientation,
@@ -163,6 +163,9 @@ fn tiff_is_raw(b: &[u8]) -> bool {
    }
    let Some(t) = Tiff::new(b) else { return false };
    let Some(ifd0) = t.first_ifd() else { return false };
+    let sony = t.ifd(ifd0).is_some_and(|(entries, _)| {
+        entries.iter().any(|e| e.tag == 0x010f && t.bytes(e).and_then(|v| v.get(..4)).is_some_and(|v| v.eq_ignore_ascii_case(b"SONY")))
+    });
    let mut stack = vec![ifd0];
    let mut seen = 0;
    while let Some(pos) = stack.pop() {
@@ -171,6 +174,12 @@ fn tiff_is_raw(b: &[u8]) -> bool {
            break;
        }
        let Some((entries, _)) = t.ifd(pos) else { continue };
+        // Sony M/S lossless ARWs retain a dummy CFA pattern, but store linear YCbCr.
+        // Requiring the raw pattern plus this layout keeps ordinary Sony TIFFs as TIFFs.
+        let uint = |tag| entries.iter().find(|e| e.tag == tag).and_then(|e| t.uint(e));
+        if sony && entries.iter().any(|e| e.tag == 0x828e) && uint(0x0103) == Some(7) && uint(0x0106) == Some(6) && uint(0x0115) == Some(3) {
+            return true;
+        }
        for e in &entries {
            match e.tag {
                0xC612 => return true, // DNGVersion
@@ -233,4 +242,38 @@ mod tests {
        b.extend_from_slice(&0u32.to_le_bytes());
        assert_eq!(sniff(&b), Some(Format::RawTiffLike));
    }
+
+    #[test]
+    fn sony_linear_ycbcr_subifd_is_raw_but_ordinary_tiff_is_not() {
+        fn fixture(compression: u32, pattern: bool) -> Vec<u8> {
+            let mut b = b"II*\0\x08\0\0\0".to_vec();
+            let entry = |b: &mut Vec<u8>, tag: u16, typ: u16, count: u32, value: u32| {
+                b.extend_from_slice(&tag.to_le_bytes());
+                b.extend_from_slice(&typ.to_le_bytes());
+                b.extend_from_slice(&count.to_le_bytes());
+                b.extend_from_slice(&value.to_le_bytes());
+            };
+            b.extend_from_slice(&2u16.to_le_bytes());
+            entry(&mut b, 0x010f, 2, 5, 38);
+            entry(&mut b, 0x014a, 4, 1, 44);
+            b.extend_from_slice(&0u32.to_le_bytes());
+            b.extend_from_slice(b"SONY\0\0");
+            b.extend_from_slice(&(if pattern { 4u16 } else { 3 }).to_le_bytes());
+            entry(&mut b, 0x0103, 3, 1, compression);
+            entry(&mut b, 0x0106, 3, 1, 6);
+            entry(&mut b, 0x0115, 3, 1, 3);
+            if pattern {
+                entry(&mut b, 0x828e, 1, 4, u32::MAX);
+            }
+            b.extend_from_slice(&0u32.to_le_bytes());
+            b
+        }
+        let mut raw = fixture(7, true);
+        assert_eq!(sniff(&raw), Some(Format::RawTiffLike));
+        assert_eq!(sniff(&fixture(7, false)), Some(Format::Tiff));
+        assert_eq!(sniff(&fixture(1, true)), Some(Format::Tiff));
+        assert_eq!(sniff(&raw[..38]), Some(Format::Tiff));
+        raw[38..42].copy_from_slice(b"TEST");
+        assert_eq!(sniff(&raw), Some(Format::Tiff));
+    }
 }
@@ -1,5 +1,6 @@
-//! TIFF decode via the `tiff` crate: 8/16/32-bit integer, 16/32/64-bit float, gray/RGB/CMYK/palette,
-//! alpha (associated or not), ICC (34675), XMP (700), orientation (274). First image only.
+//! TIFF decode via the `tiff` crate: 1/2/4/8/16/32/64-bit integer, 16/32/64-bit float, gray/RGB/CMYK,
+//! alpha (associated or not), ICC (34675), XMP (700), orientation (274). First image only. Palette
+//! (indexed-colour) images are refused by the `tiff` crate itself, on every read path.

 use crate::convert::{Buf, Meta, Model, Raw, check_size, finish};
 use crate::{DecodeOptions, Decoded, Error, Format, Result};
@@ -25,7 +26,6 @@ pub(crate) fn decode(bytes: &[u8], opts: &DecodeOptions) -> Result<Decoded> {
    let icc = tag_bytes(&mut d, Tag::IccProfile);
    let xmp = tag_bytes(&mut d, Tag::from_u16_exhaustive(700)).map(|v| String::from_utf8_lossy(&v).trim_end_matches('\0').to_string());
    let orientation = d.get_tag_u32(Tag::Orientation).ok().map(|v| v as u16);
-    let photometric = d.get_tag_u32(Tag::PhotometricInterpretation).ok();
    let planar = d.get_tag_u32(Tag::PlanarConfiguration).ok() == Some(2);
    let extra = d.get_tag_u16_vec(Tag::ExtraSamples).ok().unwrap_or_default();
    let colormap = d.get_tag_u16_vec(Tag::ColorMap).ok();
@@ -45,6 +45,9 @@ pub(crate) fn decode(bytes: &[u8], opts: &DecodeOptions) -> Result<Decoded> {
        ColorType::Multiband { bit_depth, num_samples } if num_samples >= 1 => (Model::Gray, 1, num_samples as usize, bit_depth),
        other => return Err(Error::Unsupported(F, unsupported_name(other))),
    };
+    if bits < 8 && planar && n_samples > 1 {
+        return Err(Error::Unsupported(F, "planar TIFF with samples narrower than a byte"));
+    }
    let has_alpha = n_samples > n_color && !matches!(ct, ColorType::Palette(_));
    let premultiplied = has_alpha && extra.first() == Some(&1);

@@ -52,6 +55,7 @@ pub(crate) fn decode(bytes: &[u8], opts: &DecodeOptions) -> Result<Decoded> {
    let (wu, hu) = (w as usize, h as usize);
    let n = wu * hu;
    let mut buf = match res {
+        DecodingResult::U8(v) if bits < 8 => Buf::U8(unpack(&v, wu, hu, n_samples, bits)?),
        DecodingResult::U8(v) => Buf::U8(v),
        DecodingResult::U16(v) => Buf::U16(v),
        // Rare integer widths: keep 16 significant bits (plenty for display-referred data).
@@ -94,14 +98,8 @@ pub(crate) fn decode(bytes: &[u8], opts: &DecodeOptions) -> Result<Decoded> {
        return finish(F, raw, meta, (w, h), opts);
    }

-    // WhiteIsZero → invert.
-    if photometric == Some(0) {
-        match &mut buf {
-            Buf::U8(v) => v.iter_mut().for_each(|x| *x = 255 - *x),
-            Buf::U16(v) => v.iter_mut().for_each(|x| *x = 65535 - *x),
-            Buf::F32(v) => v.iter_mut().for_each(|x| *x = 1.0 - *x),
-        }
-    }
+    // WhiteIsZero needs nothing here: the `tiff` crate inverts those samples as it reads them (and
+    // refuses WhiteIsZero layouts it can't invert), so inverting again would show a negative.

    // Drop extra samples beyond colour + one alpha.
    let keep = n_color + has_alpha as usize;
@@ -140,6 +138,29 @@ fn unsupported_name(ct: ColorType) -> &'static str {
    }
 }

+/// Samples narrower than a byte (1-bit bilevel and fax scans, 2- and 4-bit gray) arrive packed, most
+/// significant bits first, each row padded to a whole byte. Spread them out one per byte, scaled to
+/// 0–255 like any 8-bit sample.
+fn unpack(packed: &[u8], width: usize, height: usize, samples: usize, bits: u8) -> Result<Vec<u8>> {
+    if !matches!(bits, 1 | 2 | 4) {
+        return Err(Error::Unsupported(F, "TIFF samples of 3, 5, 6 or 7 bits"));
+    }
+    let bits = bits as usize;
+    let per_row = width.checked_mul(samples).ok_or_else(|| err("row too wide"))?;
+    let row_bytes = per_row.checked_mul(bits).ok_or_else(|| err("row too wide"))?.div_ceil(8);
+    if row_bytes == 0 || packed.len() / row_bytes < height {
+        return Err(err("sample buffer too short"));
+    }
+    let max = (1u8 << bits) - 1;
+    let scale = 255 / max; // 255, 85, 17: exact
+    let mut out = Vec::with_capacity(per_row.saturating_mul(height));
+    for row in packed.chunks_exact(row_bytes).take(height) {
+        let values = row.iter().flat_map(|&b| (1..=8 / bits).map(move |i| (b >> (8 - bits * i)) & max));
+        out.extend(values.take(per_row).map(|v| v * scale));
+    }
+    Ok(out)
+}
+
 fn interleave(buf: Buf, n: usize, s: usize) -> Buf {
    fn go<T: Copy + Default>(v: Vec<T>, n: usize, s: usize) -> Vec<T> {
        if v.len() < n * s {
@@ -12,6 +12,9 @@ fn err(e: impl std::fmt::Display) -> Error {

 pub(crate) fn decode(bytes: &[u8], opts: &DecodeOptions) -> Result<Decoded> {
    let mut d = image_webp::WebPDecoder::new(std::io::Cursor::new(bytes)).map_err(err)?;
+    // RIFF chunk lengths are untrusted. Metadata cannot exceed the input;
+    // otherwise a tiny truncated file can request gigabytes before read_exact fails.
+    d.set_memory_limit(bytes.len());
    let (w, h) = d.dimensions();
    check_size(F, w as u64, h as u64, opts)?;
    let alpha = d.has_alpha();
@@ -32,10 +32,46 @@ fn try_all(bytes: &[u8]) {
        let _ = decode_unguarded(bytes, f, &DecodeOptions { max_size: Some((8, 8)), max_pixels: 1 << 22 });
    }
    let _ = decode(bytes, small_opts());
-    let _ = decode_thumbnail(bytes, 16);
+    let _ = decode_thumbnail_with(bytes, &ThumbnailOptions { max_pixels: small_opts().max_pixels, ..ThumbnailOptions::new(16) });
    let _ = lightcraft_codecs::icc::parse(bytes);
 }

+#[test]
+fn webp_truncated_metadata_cannot_allocate_declared_chunk_size() {
+    let mut bytes = seeds()[5].clone();
+    let tag = bytes.windows(4).rposition(|w| w == b"XMP ").unwrap();
+    bytes[tag + 4..tag + 8].copy_from_slice(&1_946_157_060u32.to_le_bytes());
+    let decoded = decode(&bytes, small_opts()).unwrap();
+    assert_eq!((decoded.image.width, decoded.image.height), (24, 16));
+    assert!(decoded.xmp.is_none(), "invalid optional metadata is ignored");
+}
+
+#[test]
+fn thumbnail_rejects_huge_gif_before_allocating_source_pixels() {
+    // A logical screen header without a global palette; previously this reached a
+    // multi-gigabyte output allocation before discovering that no frame follows.
+    let bytes = [
+        0x47, 0x49, 0x46, 0x38, 0x39, 0x61, 0x8f, 0xa4, 0xb0, 0x3f, 0x57, 0x14, 0xe8, 0x8a, 0xf8, 0xe0, 0xc7, 0x41, 0x9d, 0x0c, 0x10, 0xde, 0x54,
+        0x24, 0xcb, 0xed, 0xff, 0x4a, 0xe7, 0xa0, 0x82, 0x10, 0xa0, 0xbc, 0xac, 0xe5, 0x33, 0x3f, 0xc9, 0x8d, 0x69, 0xf4, 0x24, 0xce, 0x99, 0x4f,
+        0x0d, 0x47, 0xa0, 0xb0, 0xf4, 0xa8, 0x59, 0xad, 0x29, 0xbd, 0x09, 0x48, 0x63, 0xea, 0x59, 0xb7, 0xb7, 0xf2, 0xa1, 0x90, 0xeb, 0x92, 0xc5,
+        0x9c, 0xde, 0xcc, 0x96, 0x67, 0xc4, 0xe5, 0x8c, 0x03, 0x50, 0xb2, 0x30, 0xf8, 0xf4, 0x69, 0x1d, 0xeb, 0xb9, 0xbd, 0x4e, 0xfb, 0xbd, 0xb6,
+        0x02,
+    ];
+    let result = decode_thumbnail(&bytes, 16);
+    assert!(matches!(result, Err(Error::TooLarge(42_127, 16_304))), "{result:?}");
+}
+
+#[test]
+fn thumbnail_respects_configured_source_pixel_limit() {
+    let image = Rgba8::from_fn(3, 2, |_, _| [40, 80, 120, 255]);
+    let bytes = encode_png(&EncodeImage::rgba8(&image), &EncodeMeta::default()).unwrap();
+    let mut opts = ThumbnailOptions::new(1);
+    opts.max_pixels = 5;
+    assert!(matches!(decode_thumbnail_with(&bytes, &opts), Err(Error::TooLarge(3, 2))));
+    opts.max_pixels = 6;
+    assert_eq!(decode_thumbnail_with(&bytes, &opts).unwrap().image.width, 1);
+}
+
 fn seeds() -> &'static Vec<Vec<u8>> {
    static S: OnceLock<Vec<Vec<u8>>> = OnceLock::new();
    S.get_or_init(|| {
@@ -245,6 +245,80 @@ fn tiff_cmyk_and_orientation() {
    assert!(red[0] > 0.99 && red[1] < 0.01 && red[2] < 0.01, "{red:?}");
 }

+/// A one-strip, uncompressed, single-sample TIFF (little-endian) whose samples are `bits` wide and
+/// already packed into `strip`, one padded row after another.
+fn packed_tiff(width: u16, height: u16, bits: u16, photometric: u16, strip: &[u8]) -> Vec<u8> {
+    const STRIP_AT: u32 = 8 + 2 + 9 * 12 + 4;
+    let short = |tag: u16, v: u16| [&tag.to_le_bytes()[..], &3u16.to_le_bytes(), &1u32.to_le_bytes(), &v.to_le_bytes(), &[0, 0]].concat();
+    let long = |tag: u16, v: u32| [&tag.to_le_bytes()[..], &4u16.to_le_bytes(), &1u32.to_le_bytes(), &v.to_le_bytes()].concat();
+    let mut b = b"II*\0".to_vec();
+    b.extend(8u32.to_le_bytes());
+    b.extend(9u16.to_le_bytes());
+    b.extend(short(256, width));
+    b.extend(short(257, height));
+    b.extend(short(258, bits));
+    b.extend(short(259, 1));
+    b.extend(short(262, photometric));
+    b.extend(long(273, STRIP_AT));
+    b.extend(short(277, 1));
+    b.extend(short(278, height));
+    b.extend(long(279, strip.len() as u32));
+    b.extend(0u32.to_le_bytes());
+    assert_eq!(b.len(), STRIP_AT as usize);
+    b.extend_from_slice(strip);
+    b
+}
+
+/// WhiteIsZero (photometric 0) gray: the lowest sample is white. The `tiff` crate already inverts these
+/// samples, and a second inversion here used to show every WhiteIsZero scan as a negative.
+#[test]
+fn tiff_white_is_zero_is_inverted_once() {
+    // Two pixels: the lowest sample, then the highest, at 8 and 16 bits.
+    for (bits, strip) in [(8, vec![0u8, 255]), (16, [0u16.to_le_bytes(), 65535u16.to_le_bytes()].concat())] {
+        for (photometric, first) in [(0, 1.0), (1, 0.0)] {
+            let d = decode(&packed_tiff(2, 1, bits, photometric, &strip), DecodeOptions::default()).unwrap();
+            let (a, b) = (d.image.get(0, 0)[1], d.image.get(1, 0)[1]);
+            assert!((a - first).abs() < 1e-6 && (b - (1.0 - first)).abs() < 1e-6, "{bits}-bit, photometric {photometric}: {a} {b}");
+        }
+    }
+}
+
+/// 1-, 2- and 4-bit samples (bilevel scans, fax images, low-depth gray) arrive packed eight, four or
+/// two to a byte with each row padded to a byte; they used to be rejected as "sample buffer too short".
+#[test]
+fn tiff_samples_narrower_than_a_byte() {
+    let gray = |d: &Decoded, x: usize, y: usize| d.image.get(x, y)[1];
+
+    // 10 × 2 bilevel: rows are 2 bytes, the last 6 bits of each are padding (set, to prove they are ignored).
+    // Row 0 alternates set/clear bits; row 1 is clear but for its last pixel.
+    let rows = [0b1010_1010, 0b1011_1111, 0b0000_0000, 0b0111_1111];
+    // What a set bit decodes to: white for BlackIsZero (1), black for WhiteIsZero (0).
+    for (photometric, set_bit) in [(1, 1.0), (0, 0.0)] {
+        let d = decode(&packed_tiff(10, 2, 1, photometric, &rows), DecodeOptions::default()).unwrap();
+        assert_eq!((d.image.width, d.image.height, d.bit_depth), (10, 2, 1));
+        assert!(d.grayscale);
+        let clear_bit = 1.0 - set_bit;
+        for x in 0..10 {
+            let want = (if x % 2 == 0 { set_bit } else { clear_bit }, if x == 9 { set_bit } else { clear_bit });
+            assert!((gray(&d, x, 0) - want.0).abs() < 1e-6, "row 0, x {x}, photometric {photometric}");
+            assert!((gray(&d, x, 1) - want.1).abs() < 1e-6, "row 1, x {x}, photometric {photometric}");
+        }
+    }
+
+    // 2-bit: 0, 1, 2, 3 → 0, 85, 170, 255. 4-bit: 0, 15, 8 → 0, 255, 136 (the row's last nibble is padding).
+    let d = decode(&packed_tiff(4, 1, 2, 1, &[0b00_01_10_11]), DecodeOptions::default()).unwrap();
+    for (x, v) in [0, 85, 170, 255].into_iter().enumerate() {
+        assert!((gray(&d, x, 0) - srgb_to_linear(v as f32 / 255.0)).abs() < 1e-6, "2-bit x {x}");
+    }
+    let d = decode(&packed_tiff(3, 1, 4, 1, &[0x0F, 0x8F]), DecodeOptions::default()).unwrap();
+    for (x, v) in [0, 255, 136].into_iter().enumerate() {
+        assert!((gray(&d, x, 0) - srgb_to_linear(v as f32 / 255.0)).abs() < 1e-6, "4-bit x {x}");
+    }
+
+    // A strip shorter than its rows is an error, never a panic.
+    assert!(decode(&packed_tiff(10, 2, 1, 1, &rows[..3]), DecodeOptions::default()).is_err());
+}
+
 #[test]
 fn webp_lossless_exact() {
    let img = gradient(31, 19);
@@ -461,7 +535,7 @@ fn thumbnail_accepts_smaller_preview_when_asked() {
        encode_jpeg(&EncodeImage::rgba8(&main), 80, ChromaSubsampling::S420, &EncodeMeta { exif: Some(&exif), ..Default::default() }).unwrap();
    let t = decode_thumbnail(&bytes, 256).unwrap();
    assert_eq!(t.source, ThumbnailSource::Scaled);
-    let t = decode_thumbnail_with(&bytes, &ThumbnailOptions { max_edge: 256, min_embedded_edge: 160 }).unwrap();
+    let t = decode_thumbnail_with(&bytes, &ThumbnailOptions { min_embedded_edge: 160, ..ThumbnailOptions::new(256) }).unwrap();
    assert_eq!(t.source, ThumbnailSource::ExifThumbnail);
    assert_eq!((t.image.width, t.image.height), (160, 120));
 }
@@ -2,7 +2,9 @@
 //!
 //! The Planckian locus uses the Kim et al. (2002) cubic approximation (1667–25000 K); outside that
 //! range it is extended linearly in mired space. Tint is a signed offset perpendicular to the locus in
-//! CIE 1960 (u, v): **positive tint = magenta** (below the locus), `Duv = −tint / TINT_SCALE`.
+//! CIE 1960 (u, v). Tint describes the **correction**: positive adds magenta, negative adds green.
+//! A positive correction neutralises a green illuminant above the locus, so its source white uses
+//! `Duv = tint / TINT_SCALE`. Bradford adaptation removes that source cast.

 use crate::{Mat3, RgbSpace, Xy, bradford};

@@ -65,11 +67,12 @@ fn locus_normal(t: f64) -> (f64, f64) {
    if ny < 0.0 { (-nx, -ny) } else { (nx, ny) }
 }

-/// Chromaticity of the white point for temperature `t` (K) and `tint`.
+/// Source illuminant chromaticity for temperature `t` (K) and correction `tint`.
+/// Positive tint means a green source white, whose correction adds magenta to the image.
 pub fn temp_tint_to_xy(t: f64, tint: f64) -> Xy {
    let (u, v) = locus_uv(t);
    let (nu, nv) = locus_normal(t);
-    let duv = -tint / TINT_SCALE;
+    let duv = tint / TINT_SCALE;
    uv_to_xy(u + nu * duv, v + nv * duv)
 }

@@ -104,7 +107,7 @@ pub fn xy_to_temp_tint(p: Xy) -> (f64, f64) {
    let (lu, lv) = locus_uv(t);
    let (nu, nv) = locus_normal(t);
    let duv = (u - lu) * nu + (v - lv) * nv;
-    (t, -duv * TINT_SCALE)
+    (t, duv * TINT_SCALE)
 }

 /// Matrix (linear RGB in `space` → same space) that white-balances a scene lit by `src` so that it
@@ -141,10 +144,18 @@ mod tests {
        let warm = temp_tint_to_xy(3000.0, 0.0);
        let cool = temp_tint_to_xy(9000.0, 0.0);
        assert!(warm.x > cool.x);
-        // positive tint is magenta: lower v
+        // A positive magenta correction specifies a greener source illuminant: higher v.
        let (_, v0) = xy_to_uv(temp_tint_to_xy(5000.0, 0.0));
        let (_, v1) = xy_to_uv(temp_tint_to_xy(5000.0, 50.0));
-        assert!(v1 < v0);
+        assert!(v1 > v0);
+    }
+
+    /// Daylight lies above the Planckian locus, so D65 reads as a small positive tint, as
+    /// Lightroom's Daylight preset (5500 K, +10) has it (#188).
+    #[test]
+    fn daylight_has_a_positive_tint() {
+        let (_, tint) = xy_to_temp_tint(crate::D65);
+        assert!((5.0..15.0).contains(&tint), "{tint}");
    }

    #[test]
@@ -13,6 +13,7 @@ lightcraft-geom = { workspace = true }
 lightcraft-color = { workspace = true }
 serde = { workspace = true }
 serde_json = { workspace = true }
+miniz_oxide = { workspace = true }

 [dev-dependencies]
 proptest = { workspace = true }
@@ -8,10 +8,12 @@

 pub mod controls;
 pub mod presets;
+pub mod segmask;
 pub mod settings;

 pub use controls::{CONTROLS, ControlSpec, Section, Track};
 pub use presets::{Preset, SettingsGroup, apply_partial, extract_groups};
+pub use segmask::SegMask;
 pub use settings::*;

 use serde_json::Value;
@@ -66,6 +68,32 @@ impl DevelopSettings {
        !self.disabled_sections.iter().any(|s| s == section)
    }

+    /// The settings as rendered: an Edit-panel section whose eye is off contributes nothing (issue
+    /// #316). Light (with its tone curve), Color (white balance, presence, the mixers, colour grading
+    /// and point colour) and Detail are reset to their defaults here; Effects, Optics, Geometry and
+    /// Calibration the pipeline switches off where it applies them. Borrowed when every section is on.
+    pub fn effective(&self) -> std::borrow::Cow<'_, DevelopSettings> {
+        let off = |section: &str| !self.section_enabled(section);
+        if !(off("light") || off("color") || off("detail")) {
+            return std::borrow::Cow::Borrowed(self);
+        }
+        let mut d = self.clone();
+        if off("light") {
+            d.reset_section(Section::Light);
+            d.reset_section(Section::Curve);
+        }
+        if off("color") {
+            for section in [Section::Color, Section::Mixer, Section::BwMix, Section::Grading, Section::PointColor] {
+                d.reset_section(section);
+            }
+            d.point_colors.clear();
+        }
+        if off("detail") {
+            d.reset_section(Section::Detail);
+        }
+        std::borrow::Cow::Owned(d)
+    }
+
    pub fn set_section_enabled(&mut self, section: &str, on: bool) {
        self.disabled_sections.retain(|s| s != section);
        if !on {
@@ -0,0 +1,183 @@
+//! Model segmentations stored with a mask ([`SegMask`]), so rendering never needs the model.
+
+use serde::{Deserialize, Serialize};
+
+/// Logits are stored in steps of 1/`SCALE`, clamped to ±127/`SCALE` (≈ ±15.9: a sigmoid of
+/// 1 − 1.2e-7, i.e. fully in or out).
+const SCALE: f32 = 8.0;
+/// Largest grid a stored segmentation may claim (hostile input caps the allocation).
+pub const MAX_SIDE: usize = 1024;
+
+/// A segmentation computed by a model (SAM 3 in `lightcraft-segment`): `side × side` logits
+/// over the uncropped, oriented image stretched to a square (row `y`, column `x` covers
+/// normalized `((x + 0.5) / side, (y + 0.5) / side)`), quantized to `i8`, deflated and base64
+/// encoded. Coverage at a point is the sigmoid of the bilinearly sampled logit, so edges stay
+/// smooth at any output size.
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+pub struct SegMask {
+    pub side: u32,
+    pub data: String,
+    /// The part of the image the grid covers, normalized `[x0, y0, x1, y1]` (`None` = all of
+    /// it). A zoomed-in pass over one object covers just its surroundings, at a higher
+    /// resolution than a pass over the whole photo.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub rect: Option<[f64; 4]>,
+}
+
+impl SegMask {
+    /// From `side × side` logits over the whole image.
+    pub fn from_logits(side: usize, logits: &[f32]) -> SegMask {
+        let q: Vec<u8> = logits.iter().take(side * side).map(|l| ((l * SCALE).round().clamp(-127.0, 127.0) as i8) as u8).collect();
+        let z = miniz_oxide::deflate::compress_to_vec(&q, 8);
+        SegMask { side: side as u32, data: base64_encode(&z), rect: None }
+    }
+
+    /// From `side × side` logits over the part `rect` of the image.
+    pub fn from_logits_in(side: usize, logits: &[f32], rect: [f64; 4]) -> SegMask {
+        SegMask { rect: Some(rect), ..SegMask::from_logits(side, logits) }
+    }
+
+    /// The covered part, normalized (the whole image without a `rect`); `None` when damaged.
+    pub fn bounds(&self) -> Option<[f64; 4]> {
+        let r = self.rect.unwrap_or([0.0, 0.0, 1.0, 1.0]);
+        (r.iter().all(|v| v.is_finite()) && r[2] > r[0] && r[3] > r[1]).then_some(r)
+    }
+
+    /// The logits, or `None` when the data is damaged or claims an absurd size.
+    pub fn logits(&self) -> Option<Vec<f32>> {
+        let side = self.side as usize;
+        if side == 0 || side > MAX_SIDE {
+            return None;
+        }
+        let z = base64_decode(&self.data)?;
+        let q = miniz_oxide::inflate::decompress_to_vec_with_limit(&z, side * side).ok()?;
+        (q.len() == side * side).then(|| q.iter().map(|b| f32::from(*b as i8) / SCALE).collect())
+    }
+}
+
+/// Most zoomed-in detail patches one AI mask component keeps (the app makes one; each costs a
+/// decode per render, so a hostile document can't make rendering explode).
+pub const MAX_DETAIL: usize = 4;
+
+/// Deserialize a component's detail patches, keeping at most [`MAX_DETAIL`] (the rest are
+/// skipped without being decoded).
+pub(crate) fn de_detail<'de, D: serde::Deserializer<'de>>(d: D) -> Result<Vec<SegMask>, D::Error> {
+    struct Capped;
+    impl<'de> serde::de::Visitor<'de> for Capped {
+        type Value = Vec<SegMask>;
+        fn expecting(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+            f.write_str("a list of segmentations")
+        }
+        fn visit_seq<A: serde::de::SeqAccess<'de>>(self, mut seq: A) -> Result<Vec<SegMask>, A::Error> {
+            let mut out = Vec::new();
+            while out.len() < MAX_DETAIL {
+                match seq.next_element::<SegMask>()? {
+                    Some(m) => out.push(m),
+                    None => return Ok(out),
+                }
+            }
+            while seq.next_element::<serde::de::IgnoredAny>()?.is_some() {}
+            Ok(out)
+        }
+    }
+    d.deserialize_seq(Capped)
+}
+
+const B64: &[u8; 64] = b"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
+fn base64_encode(bytes: &[u8]) -> String {
+    let mut out = String::with_capacity(bytes.len().div_ceil(3) * 4);
+    for chunk in bytes.chunks(3) {
+        let b = [chunk.first().copied().unwrap_or(0), chunk.get(1).copied().unwrap_or(0), chunk.get(2).copied().unwrap_or(0)];
+        let n = (u32::from(b[0]) << 16) | (u32::from(b[1]) << 8) | u32::from(b[2]);
+        for i in 0..4 {
+            if i <= chunk.len() {
+                out.push(char::from(B64[((n >> (18 - 6 * i)) & 63) as usize]));
+            } else {
+                out.push('=');
+            }
+        }
+    }
+    out
+}
+
+fn base64_decode(s: &str) -> Option<Vec<u8>> {
+    let mut out = Vec::with_capacity(s.len() / 4 * 3);
+    let (mut acc, mut bits) = (0u32, 0u32);
+    for c in s.bytes().filter(|c| !c.is_ascii_whitespace()) {
+        if c == b'=' {
+            break;
+        }
+        let v = B64.iter().position(|b| *b == c)? as u32;
+        acc = (acc << 6) | v;
+        bits += 6;
+        if bits >= 8 {
+            bits -= 8;
+            out.push((acc >> bits) as u8);
+            acc &= (1 << bits) - 1;
+        }
+    }
+    Some(out)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn base64_round_trips() {
+        for n in 0..10 {
+            let v: Vec<u8> = (0..n).map(|i| (i * 37 + 11) as u8).collect();
+            assert_eq!(base64_decode(&base64_encode(&v)).unwrap(), v);
+        }
+        assert_eq!(base64_encode(b"Man"), "TWFu");
+        assert_eq!(base64_encode(b"Ma"), "TWE=");
+        assert!(base64_decode("TW!u").is_none());
+    }
+
+    #[test]
+    fn logits_round_trip_quantized() {
+        let side = 16;
+        let l: Vec<f32> = (0..side * side).map(|i| (i as f32 - 128.0) / 4.0).collect();
+        let m = SegMask::from_logits(side, &l);
+        let back = m.logits().unwrap();
+        for (a, b) in l.iter().zip(&back) {
+            assert!((a.clamp(-127.0 / SCALE, 127.0 / SCALE) - b).abs() <= 0.5 / SCALE + 1e-6);
+        }
+    }
+
+    #[test]
+    fn a_hostile_document_keeps_at_most_max_detail_patches() {
+        let patch = serde_json::to_value(SegMask::from_logits(4, &[1.0; 16])).unwrap();
+        let shape = serde_json::json!({"kind": "object", "hint": [{"x": 0.5, "y": 0.5}], "detail": vec![patch; 10_000]});
+        let s: crate::MaskShape = serde_json::from_value(shape).unwrap();
+        let crate::MaskShape::Object { detail, .. } = s else { panic!("an Object") };
+        assert_eq!(detail.len(), MAX_DETAIL);
+        // and a whole develop document with them still loads
+        let mut d = crate::DevelopSettings::default();
+        d.masks.push(crate::Mask {
+            id: 1,
+            components: vec![crate::MaskComponent {
+                name: None,
+                op: crate::MaskOp::Add,
+                invert: false,
+                shape: crate::MaskShape::Prompt { text: "x".into(), seg: None, detail: vec![SegMask::from_logits(4, &[1.0; 16]); 50], edge: 0.0 },
+            }],
+            ..Default::default()
+        });
+        let back: crate::DevelopSettings = serde_json::from_str(&serde_json::to_string(&d).unwrap()).unwrap();
+        let crate::MaskShape::Prompt { detail, .. } = &back.masks[0].components[0].shape else { panic!("a Prompt") };
+        assert_eq!(detail.len(), MAX_DETAIL);
+    }
+
+    #[test]
+    fn damaged_data_is_none() {
+        let mut m = SegMask::from_logits(8, &[1.0; 64]);
+        m.side = 9;
+        assert!(m.logits().is_none(), "size mismatch");
+        m.side = 100_000;
+        assert!(m.logits().is_none(), "absurd size");
+        assert!(SegMask { side: 8, data: "not base64 !".into(), rect: None }.logits().is_none());
+        assert!(SegMask { rect: Some([0.5, 0.0, 0.2, 1.0]), ..SegMask::from_logits(2, &[0.0; 4]) }.bounds().is_none());
+    }
+}
@@ -158,6 +158,7 @@ impl WbMode {
 pub struct WhiteBalance {
    pub mode: WbMode,
    pub temp: f64,
+    /// Correction direction: negative adds green, positive adds magenta.
    pub tint: f64,
 }

@@ -539,8 +540,9 @@ impl Default for Optics {
    }
 }

-/// Lens corrections embedded in a DNG file (`OpcodeList3`: `WarpRectilinear`, `FixVignetteRadial`), converted
-/// to the oriented, default-cropped image. This is camera/file data (stored on the photo record, not in the develop
+/// Lens corrections embedded in the file, converted to the oriented, default-cropped image: a DNG's `OpcodeList3`
+/// (`WarpRectilinear`, `FixVignetteRadial`), or a raw reader's equivalent of the camera's own correction (Panasonic /
+/// Leica RW2 distortion, `lightcraft_raw`'s `vendor/rw2.rs`). This is camera/file data (stored on the photo record, not in the develop
 /// settings); "Enable Profile Corrections" applies it, scaled by the profile distortion/vignetting amounts.
 /// LightCraft never uses Adobe LCP lens profiles.
 #[derive(Clone, Copy, Debug, Default, PartialEq, Serialize, Deserialize)]
@@ -772,8 +774,33 @@ pub enum MaskShape {
    Subject,
    Sky,
    Background,
+    /// One object picked by clicks (SAM 3 point prompts): `hint` holds the clicks that include,
+    /// `exclude` the ones that exclude; `seg` the segmentation computed from them.
    Object {
        hint: Vec<Point>,
+        #[serde(default, skip_serializing_if = "Vec::is_empty")]
+        exclude: Vec<Point>,
+        #[serde(default, skip_serializing_if = "Option::is_none")]
+        seg: Option<crate::SegMask>,
+        /// Zoomed-in passes over parts of the image (higher resolution than `seg`), used
+        /// inside their rectangles.
+        #[serde(default, skip_serializing_if = "Vec::is_empty", deserialize_with = "crate::segmask::de_detail")]
+        detail: Vec<crate::SegMask>,
+        /// Edge −100..100: below 0 harder (a steeper transition), above 0 softer (feathered).
+        #[serde(default, skip_serializing_if = "is_zero")]
+        edge: f64,
+    },
+    /// Everything a description names ("sky", "the red car": SAM 3 concept prompts); `seg` is
+    /// the segmentation computed for it.
+    Prompt {
+        text: String,
+        #[serde(default, skip_serializing_if = "Option::is_none")]
+        seg: Option<crate::SegMask>,
+        #[serde(default, skip_serializing_if = "Vec::is_empty", deserialize_with = "crate::segmask::de_detail")]
+        detail: Vec<crate::SegMask>,
+        /// Edge −100..100, as for `Object`.
+        #[serde(default, skip_serializing_if = "is_zero")]
+        edge: f64,
    },
    People {
        person: u32,
@@ -30,6 +30,14 @@ serde_json = { workspace = true }
 thiserror = { workspace = true }
 log = { workspace = true }
 ab_glyph = { workspace = true }
+# Apply the font’s vertical substitutions and origins to Japanese watermarks.
+harfrust = { version = "0.12", default-features = false, features = ["std"] }
+lightcraft-segment = { workspace = true, optional = true }
+
+[features]
+# AI masks with SAM 3 (Object / Describe). Off for the web and CLI builds.
+sam = ["dep:lightcraft-segment"]

 [dev-dependencies]
 libc = { workspace = true }
+lightcraft-tiff = { workspace = true }
@@ -0,0 +1,86 @@
+//! Optional build input: with `CRAFT_FONTS_DIR=<storytold/craft-fonts checkout>`, embed every font
+//! in its `fonts/manifest.txt` as `CRAFT_FONTS` (see src/fonts.rs). Unset, `CRAFT_FONTS` is empty.
+//! Recipe from craft-fonts' docs/integration.md; craft-fonts is never a Cargo dependency, and this
+//! script only reads a local directory (no network).
+//!
+//! wasm32 (the web build) embeds only the UI font, BIZ UDPGothic Regular (~4.5 MB), to keep the
+//! `.wasm` within the web size budget (Cloudflare serves at most 25 MiB per file); the export
+//! watermark falls back to it there. Native builds embed every font.
+use std::fmt::Write as _;
+use std::path::{Path, PathBuf};
+
+fn main() {
+    println!("cargo::rerun-if-changed=build.rs");
+    println!("cargo::rerun-if-env-changed=CRAFT_FONTS_DIR");
+    println!("cargo::rerun-if-env-changed=CRAFT_FONTS_REQUIRED");
+    let mut src = String::from("pub static CRAFT_FONTS: &[CraftFont] = &[\n");
+    let mut embedded = 0;
+    if let Some(dir) = std::env::var_os("CRAFT_FONTS_DIR").map(PathBuf::from).map(resolve) {
+        match craft_fonts(&dir) {
+            Ok(entries) => {
+                embedded = entries.lines().count();
+                src.push_str(&entries);
+            }
+            Err(e) if std::env::var_os("CRAFT_FONTS_REQUIRED").is_some() => {
+                println!("cargo::error=CRAFT_FONTS_DIR={}: {e}", dir.display());
+            }
+            Err(e) => println!("cargo::warning=building without craft-fonts: CRAFT_FONTS_DIR={}: {e}", dir.display()),
+        }
+    }
+    src.push_str("];\n");
+    // Without them the app still runs and every language still selectable, so Chinese and Japanese
+    // just paint boxes — the one failure a user cannot diagnose from what they see.
+    if embedded == 0 {
+        println!(
+            "cargo::warning=no craft-fonts embedded: Chinese and Japanese text will render as empty boxes. \
+             Clone https://github.com/storytold/craft-fonts next to this repo and rebuild with \
+             CRAFT_FONTS_DIR=../craft-fonts"
+        );
+    }
+    let out = PathBuf::from(std::env::var_os("OUT_DIR").unwrap_or_default()).join("craft_fonts.rs");
+    if let Err(e) = std::fs::write(&out, src) {
+        println!("cargo::error=writing {}: {e}", out.display());
+    }
+}
+
+/// Resolve a relative `CRAFT_FONTS_DIR` against both roots a caller might mean: a build script's
+/// cwd is the *package* root (`crates/engine`), while the `../craft-fonts` the README and
+/// craft-fonts' docs use is written relative to the *workspace* root and would otherwise resolve
+/// to `crates/craft-fonts`.
+fn resolve(dir: PathBuf) -> PathBuf {
+    if dir.is_absolute() {
+        return dir;
+    }
+    let package = PathBuf::from(std::env::var_os("CARGO_MANIFEST_DIR").unwrap_or_default());
+    let workspace = package.parent().and_then(Path::parent).unwrap_or(package.as_path());
+    let candidates = [workspace.join(&dir), package.join(&dir)];
+    candidates.iter().find(|candidate| candidate.is_dir()).cloned().unwrap_or_else(|| candidates[0].clone())
+}
+
+/// One `CraftFont { .. }` initialiser per manifest line.
+fn craft_fonts(dir: &Path) -> Result<String, String> {
+    let manifest = dir.join("fonts/manifest.txt");
+    println!("cargo::rerun-if-changed={}", manifest.display());
+    let text = std::fs::read_to_string(&manifest).map_err(|e| format!("{}: {e}", manifest.display()))?;
+    let wasm = std::env::var("CARGO_CFG_TARGET_ARCH").is_ok_and(|a| a == "wasm32");
+    let mut out = String::new();
+    for line in text.lines().map(str::trim).filter(|l| !l.is_empty() && !l.starts_with('#')) {
+        let f: Vec<&str> = line.split(" | ").map(str::trim).collect();
+        let [family, style, file, scripts, ..] = f.as_slice() else {
+            return Err(format!("malformed manifest line: {line}"));
+        };
+        if wasm && (*family, *style) != ("BIZ UDPGothic", "Regular") {
+            continue;
+        }
+        let path = dir.join(file).canonicalize().map_err(|e| format!("{file}: {e}"))?;
+        println!("cargo::rerun-if-changed={}", path.display());
+        let scripts: Vec<String> = scripts.split(',').map(|s| format!("{:?}", s.trim())).collect();
+        let _ = writeln!(
+            out,
+            "    CraftFont {{ family: {family:?}, style: {style:?}, scripts: &[{}], bytes: include_bytes!({:?}) }},",
+            scripts.join(", "),
+            path.display().to_string(),
+        );
+    }
+    Ok(out)
+}
@@ -93,7 +93,9 @@ fn main() {
        for path in &args {
            let bytes = std::fs::read(path).expect("read");
            println!("{path}");
-            let raw = lightcraft_raw::decode(&bytes).expect("decode");
+            let mut raw = lightcraft_raw::decode(&bytes).expect("decode");
+            // as the loader does: lens corrections are applied by the pipeline, not in the raw develop
+            raw.opcodes.list3.retain(|op| !op.is_lens_correction());
            println!("  {}×{} cpp {} cfa {:?}", raw.width, raw.height, raw.cpp, raw.cfa.as_ref().map(|c| c.name()));
            println!("  {:<36} {}", "raw decode:", best(n, || drop(lightcraft_raw::decode(&bytes).expect("decode"))));
            println!("  {:<36} {}", "normalize:", best(n, || drop(raw.normalized().expect("norm"))));
@@ -0,0 +1,215 @@
+//! Is a file there? — answered without blocking the caller.
+//!
+//! On a sleeping NAS, a dropped share or a USB drive spinning up, one `stat` can take as long as
+//! the OS or SMB timeout. The UI asks about files every frame (grid cells, the Info panel, the
+//! Missing Photos view), so in the app the answers come from a cache that a worker thread fills
+//! ([`Availability::run_in_background`]): an unknown file is reported as `None` ("assume it is
+//! there"; the render worker finds out if it isn't), known answers are rechecked after
+//! [`RECHECK`]. Everywhere else (CLI, MCP, tests) the default is synchronous: every question is a
+//! fresh check, as before.
+
+use std::collections::{HashMap, HashSet, VecDeque};
+use std::sync::{Arc, Mutex, MutexGuard, PoisonError};
+use std::time::Duration;
+
+/// Checks whether a path exists (injectable: tests use a slow one).
+pub type ExistsProbe = Arc<dyn Fn(&str) -> bool + Send + Sync>;
+/// Called (from the worker) when an answer changed, e.g. to repaint the UI.
+pub type Waker = Arc<dyn Fn() + Send + Sync>;
+
+/// How long a cached answer is used before it is checked again (it is still returned meanwhile).
+pub const RECHECK: Duration = Duration::from_secs(15);
+
+fn fs_exists(path: &str) -> bool {
+    // the browser build has no file system: its originals are always "there"
+    cfg!(target_arch = "wasm32") || std::path::Path::new(path).exists()
+}
+
+#[derive(Default)]
+struct State {
+    /// path → (exists, when checked)
+    known: HashMap<String, (bool, std::time::Instant)>,
+    queue: VecDeque<String>,
+    queued: HashSet<String>,
+    worker: bool,
+    /// Bumped whenever an answer changes (callers recompute what depends on it).
+    generation: u64,
+}
+
+fn lock(m: &Mutex<State>) -> MutexGuard<'_, State> {
+    m.lock().unwrap_or_else(PoisonError::into_inner)
+}
+
+/// File availability, synchronous or cached + background-checked. Cloning shares the cache.
+#[derive(Clone)]
+pub struct Availability {
+    probe: ExistsProbe,
+    background: Option<Waker>,
+    state: Arc<Mutex<State>>,
+}
+
+impl Default for Availability {
+    fn default() -> Self {
+        Self { probe: Arc::new(fs_exists), background: None, state: Arc::default() }
+    }
+}
+
+impl std::fmt::Debug for Availability {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("Availability").field("background", &self.background.is_some()).finish()
+    }
+}
+
+impl Availability {
+    /// Replace the existence check (tests: a slow or counting probe). Forgets cached answers.
+    pub fn set_probe(&mut self, probe: ExistsProbe) {
+        self.probe = probe;
+        let mut st = lock(&self.state);
+        st.known.clear();
+        st.generation += 1;
+    }
+
+    /// Answer from the cache and check on a worker thread from now on; `wake` runs when an
+    /// answer changed. No effect in the browser build (no threads, no file system).
+    pub fn run_in_background(&mut self, wake: Waker) {
+        if cfg!(target_arch = "wasm32") {
+            return;
+        }
+        self.background = Some(wake);
+    }
+
+    /// The existence check itself (blocking: for worker threads, e.g. the Rename preview's).
+    pub fn probe(&self) -> ExistsProbe {
+        self.probe.clone()
+    }
+
+    pub fn is_background(&self) -> bool {
+        self.background.is_some()
+    }
+
+    /// Does `path` exist? Synchronous mode: checked now. Background mode: the cached answer
+    /// (`None` while unknown); unknown or stale answers are queued for the worker.
+    pub fn exists(&self, path: &str) -> Option<bool> {
+        let Some(wake) = &self.background else {
+            return Some((self.probe)(path));
+        };
+        let mut st = lock(&self.state);
+        let now = std::time::Instant::now();
+        let cached = st.known.get(path).copied();
+        if cached.is_none_or(|(_, at)| now.saturating_duration_since(at) >= RECHECK) && !st.queued.contains(path) {
+            st.queued.insert(path.to_string());
+            st.queue.push_back(path.to_string());
+            if !st.worker {
+                st.worker = true;
+                drop(st);
+                self.spawn_worker(wake.clone());
+                return cached.map(|c| c.0);
+            }
+        }
+        cached.map(|c| c.0)
+    }
+
+    /// Known to be missing (unknown counts as present).
+    pub fn is_offline(&self, path: &str) -> bool {
+        self.exists(path) == Some(false)
+    }
+
+    /// Changes whenever a cached answer changes.
+    pub fn generation(&self) -> u64 {
+        lock(&self.state).generation
+    }
+
+    /// Paths waiting for the worker.
+    pub fn pending(&self) -> usize {
+        lock(&self.state).queue.len()
+    }
+
+    fn spawn_worker(&self, wake: Waker) {
+        let (state, probe) = (self.state.clone(), self.probe.clone());
+        let started = std::thread::Builder::new().name("lc-availability".into()).spawn(move || {
+            loop {
+                let path = {
+                    let mut st = lock(&state);
+                    let Some(p) = st.queue.pop_front() else {
+                        st.worker = false;
+                        return;
+                    };
+                    p
+                };
+                let ok = probe(&path);
+                let changed = {
+                    let mut st = lock(&state);
+                    st.queued.remove(&path);
+                    let prev = st.known.insert(path, (ok, std::time::Instant::now()));
+                    let changed = prev.map(|p| p.0) != Some(ok);
+                    if changed {
+                        st.generation += 1;
+                    }
+                    changed
+                };
+                if changed {
+                    wake();
+                }
+            }
+        });
+        if started.is_err() {
+            // try again on the next question
+            lock(&self.state).worker = false;
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::sync::atomic::{AtomicUsize, Ordering};
+
+    #[test]
+    fn synchronous_by_default() {
+        let mut a = Availability::default();
+        let n = Arc::new(AtomicUsize::new(0));
+        let c = n.clone();
+        a.set_probe(Arc::new(move |p| {
+            c.fetch_add(1, Ordering::SeqCst);
+            p == "here"
+        }));
+        assert_eq!(a.exists("here"), Some(true));
+        assert_eq!(a.exists("gone"), Some(false));
+        assert_eq!(a.exists("gone"), Some(false));
+        assert_eq!(n.load(Ordering::SeqCst), 3, "every question is a fresh check");
+    }
+
+    #[test]
+    fn background_answers_from_the_cache_without_blocking() {
+        let mut a = Availability::default();
+        let caller = std::thread::current().id();
+        let on_caller = Arc::new(AtomicUsize::new(0));
+        let c = on_caller.clone();
+        a.set_probe(Arc::new(move |p| {
+            if std::thread::current().id() == caller {
+                c.fetch_add(1, Ordering::SeqCst);
+            }
+            std::thread::sleep(Duration::from_millis(200)); // a sleeping NAS
+            p == "here"
+        }));
+        let woke = Arc::new(AtomicUsize::new(0));
+        let w = woke.clone();
+        a.run_in_background(Arc::new(move || {
+            w.fetch_add(1, Ordering::SeqCst);
+        }));
+        let t0 = std::time::Instant::now();
+        assert_eq!(a.exists("here"), None, "unknown at first");
+        assert_eq!(a.exists("gone"), None);
+        assert!(t0.elapsed() < Duration::from_millis(150), "the caller never waits for the probe");
+        let deadline = std::time::Instant::now() + Duration::from_secs(20);
+        while (a.exists("here").is_none() || a.exists("gone").is_none()) && std::time::Instant::now() < deadline {
+            std::thread::sleep(Duration::from_millis(10));
+        }
+        assert_eq!(a.exists("here"), Some(true));
+        assert_eq!(a.exists("gone"), Some(false));
+        assert!(a.is_offline("gone") && !a.is_offline("here") && !a.is_offline("unknown"));
+        assert_eq!(on_caller.load(Ordering::SeqCst), 0, "never probed on the calling thread");
+        assert!(woke.load(Ordering::SeqCst) >= 2);
+        assert!(a.generation() >= 2);
+    }
+}
@@ -0,0 +1,316 @@
+//! Camera colour profiles of our own, pooled from many photos of one camera model.
+//!
+//! A raw file without colour matrices (Sony ARW, Nikon NEF, Fujifilm RAF) gets its look fitted to its own embedded camera
+//! JPEG (`camera_preview`), but one photo shows too little of some colours: a lime shirt covering a
+//! few dozen proxy pixels next to a hillside of foliage at the same hue. `lightcraft-cli calibrate`
+//! pools the colour pairs of many photos per model and fits one matrix and hue/saturation/value
+//! table; photos of that model then only fit their tone and chroma curves.
+//!
+//! Profiles are JSON files (`<model>.json`) in [`dir`]: `LIGHTCRAFT_CAMERA_PROFILES`, else
+//! `<config>/camera-profiles`; a local profile replaces the one built in ([`BUNDLED`], from
+//! `assets/camera-profiles/`). They are read once per process; a damaged or hostile file is
+//! ignored with a warning. They hold aggregate colour statistics only, never image content.
+use lightcraft_color::Mat3;
+use lightcraft_raw::profile::HsvTable;
+use serde::{Deserialize, Serialize};
+use std::collections::HashMap;
+use std::path::{Path, PathBuf};
+use std::sync::{Arc, Mutex, OnceLock, PoisonError};
+
+/// Format version of the profile files.
+const VERSION: u32 = 1;
+/// Largest profile file read (a 5 × 72 × 5 table is ~60 KB of JSON).
+const MAX_FILE: u64 = 4 << 20;
+
+/// Profiles built into LightCraft (`assets/camera-profiles/`, see `assets/ATTRIBUTION.md`):
+/// `(model, JSON)`.
+pub const BUNDLED: &[(&str, &str)] = &[
+    ("ILCE-7M4", include_str!("../../../assets/camera-profiles/ILCE-7M4.json")),
+    ("X-H2S", include_str!("../../../assets/camera-profiles/X-H2S.json")),
+    ("X-T4", include_str!("../../../assets/camera-profiles/X-T4.json")),
+];
+
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+pub struct CameraProfile {
+    pub version: u32,
+    /// The camera model as the files report it (Exif `Model`), e.g. `ILCE-7M4`.
+    pub model: String,
+    /// Photos and colour pairs the profile was fitted on.
+    pub files: usize,
+    pub samples: usize,
+    /// White-balanced camera RGB (with the baseline exposure) → linear Rec.2020, rows.
+    matrix: [[f64; 3]; 3],
+    /// Hue/saturation/value correction after `matrix` (linear ProPhoto RGB).
+    pub hue_sat: Option<HsvTable>,
+}
+
+impl CameraProfile {
+    pub fn new(model: &str, files: usize, samples: usize, matrix: Mat3, hue_sat: Option<HsvTable>) -> CameraProfile {
+        CameraProfile { version: VERSION, model: model.to_owned(), files, samples, matrix: matrix.0, hue_sat }
+    }
+
+    pub fn matrix(&self) -> Mat3 {
+        Mat3(self.matrix)
+    }
+
+    /// Whether the data is usable (bounded matrix, table shape matching its data).
+    fn valid(&self) -> bool {
+        let matrix = self.matrix.iter().flatten().all(|v| v.is_finite() && v.abs() < 8.0) && Mat3(self.matrix).inverse().is_some();
+        let table = self.hue_sat.as_ref().is_none_or(|t| {
+            let dims = (1..=4096).contains(&t.hue_divisions) && (2..=4096).contains(&t.sat_divisions) && (1..=4096).contains(&t.val_divisions);
+            let len = t.hue_divisions.checked_mul(t.sat_divisions).and_then(|n| n.checked_mul(t.val_divisions));
+            dims && len == Some(t.data.len()) && t.data.iter().flatten().all(|v| v.is_finite()) && t.data.iter().all(|e| e[1] >= 0.0 && e[2] >= 0.0)
+        });
+        self.version == VERSION && !self.model.is_empty() && matrix && table
+    }
+}
+
+/// LightCraft's configuration folder (settings, GPU marker, camera profiles).
+pub fn config_dir() -> Option<PathBuf> {
+    if cfg!(target_os = "macos") {
+        std::env::var_os("HOME").map(|h| PathBuf::from(h).join("Library/Application Support/LightCraft"))
+    } else if cfg!(windows) {
+        std::env::var_os("APPDATA").map(|a| PathBuf::from(a).join("LightCraft"))
+    } else {
+        std::env::var_os("XDG_CONFIG_HOME")
+            .map(PathBuf::from)
+            .or_else(|| std::env::var_os("HOME").map(|h| PathBuf::from(h).join(".config")))
+            .map(|c| c.join("lightcraft"))
+    }
+}
+
+/// Where camera profiles are read from and written to.
+pub fn dir() -> Option<PathBuf> {
+    std::env::var_os("LIGHTCRAFT_CAMERA_PROFILES").map(PathBuf::from).or_else(|| config_dir().map(|d| d.join("camera-profiles")))
+}
+
+/// File name of `model`'s profile: letters, digits, `-` and `_` kept, anything else `_`.
+pub fn file_name(model: &str) -> String {
+    let name: String = model.trim().chars().map(|c| if c.is_ascii_alphanumeric() || c == '-' || c == '_' { c } else { '_' }).collect();
+    format!("{name}.json")
+}
+
+/// Read and validate a profile file.
+pub fn load(path: &Path) -> Result<CameraProfile, String> {
+    let size = std::fs::metadata(path).map_err(|e| format!("{}: {e}", path.display()))?.len();
+    if size > MAX_FILE {
+        return Err(format!("{}: {size} bytes is too large for a camera profile", path.display()));
+    }
+    let bytes = std::fs::read(path).map_err(|e| format!("{}: {e}", path.display()))?;
+    parse(&bytes, &path.display().to_string())
+}
+
+/// Parse and validate a profile's JSON (`origin` names it in errors).
+fn parse(json: &[u8], origin: &str) -> Result<CameraProfile, String> {
+    let profile: CameraProfile = serde_json::from_slice(json).map_err(|e| format!("{origin}: {e}"))?;
+    if !profile.valid() {
+        return Err(format!("{origin}: not a usable camera profile (version {}, model {:?})", profile.version, profile.model));
+    }
+    Ok(profile)
+}
+
+/// The built-in profile for `model`, if any.
+fn bundled(model: &str) -> Option<CameraProfile> {
+    let (_, json) = BUNDLED.iter().find(|(m, _)| *m == model)?;
+    parse(json.as_bytes(), &format!("built-in profile {model}")).inspect_err(|e| eprintln!("lightcraft: ignoring camera profile {e}")).ok()
+}
+
+/// Write `profile` to `dir` (created if needed) as `<model>.json`; returns the path.
+pub fn save(profile: &CameraProfile, dir: &Path) -> Result<PathBuf, String> {
+    std::fs::create_dir_all(dir).map_err(|e| format!("{}: {e}", dir.display()))?;
+    let path = dir.join(file_name(&profile.model));
+    let json = serde_json::to_vec_pretty(profile).map_err(|e| e.to_string())?;
+    let tmp = path.with_extension("json.tmp");
+    std::fs::write(&tmp, json).map_err(|e| format!("{}: {e}", tmp.display()))?;
+    std::fs::rename(&tmp, &path).map_err(|e| format!("{}: {e}", path.display()))?;
+    Ok(path)
+}
+
+fn cache() -> &'static Mutex<HashMap<String, Option<Arc<CameraProfile>>>> {
+    static CACHE: OnceLock<Mutex<HashMap<String, Option<Arc<CameraProfile>>>>> = OnceLock::new();
+    CACHE.get_or_init(Default::default)
+}
+
+/// The profile for camera `model`: from [`dir`], else built in; read once per process.
+pub fn get(model: &str) -> Option<Arc<CameraProfile>> {
+    let model = model.trim();
+    if model.is_empty() {
+        return None;
+    }
+    let mut cache = cache().lock().unwrap_or_else(PoisonError::into_inner);
+    if let Some(hit) = cache.get(model) {
+        return hit.clone();
+    }
+    let path = dir().map(|d| d.join(file_name(model)));
+    let profile = match path {
+        Some(path) if path.is_file() => match load(&path) {
+            Ok(p) if p.model.trim() == model => Some(Arc::new(p)),
+            Ok(p) => {
+                eprintln!("lightcraft: ignoring camera profile {}: it is for {:?}, not {model:?}", path.display(), p.model);
+                None
+            }
+            Err(e) => {
+                eprintln!("lightcraft: ignoring camera profile {e}");
+                None
+            }
+        },
+        _ => None,
+    };
+    let profile = profile.or_else(|| bundled(model).map(Arc::new));
+    cache.insert(model.to_owned(), profile.clone());
+    profile
+}
+
+/// Changes when the profiles folder's contents change (per process): part of the render cache
+/// keys, so thumbnails rendered before a profile existed are not reused after.
+pub fn cache_key() -> u64 {
+    static KEY: OnceLock<u64> = OnceLock::new();
+    *KEY.get_or_init(|| {
+        let entries = dir().and_then(|d| std::fs::read_dir(d).ok());
+        let mut files: Vec<(String, u64, u64)> = entries
+            .into_iter()
+            .flatten()
+            .flatten()
+            .filter(|e| e.path().extension().is_some_and(|x| x == "json"))
+            .filter_map(|e| {
+                let meta = e.metadata().ok()?;
+                let modified = meta.modified().ok()?.duration_since(std::time::UNIX_EPOCH).ok()?.as_secs();
+                Some((e.file_name().to_string_lossy().into_owned(), meta.len(), modified))
+            })
+            .collect();
+        files.sort();
+        let mut h = lightcraft_preview::Hasher128::new();
+        for (name, len, modified) in &files {
+            h.str(name).u64(*len).u64(*modified);
+        }
+        for (model, json) in BUNDLED {
+            h.str(model).str(json);
+        }
+        h.finish().0 as u64
+    })
+}
+
+/// Per camera model: the photos read and their pooled colour pairs.
+#[derive(Default)]
+pub struct Pool {
+    models: HashMap<String, (usize, Vec<([f64; 3], [f64; 3])>)>,
+}
+
+/// Most colour pairs kept per photo, so a few busy photos can't dominate a profile.
+const PAIRS_PER_FILE: usize = 4000;
+
+impl Pool {
+    /// Add one raw file's colour pairs. `Ok(None)` when the file can't contribute (not an ARW,
+    /// NEF or RAF without colour matrices, no usable camera JPEG, too little colour).
+    pub fn add(&mut self, bytes: &[u8]) -> Result<Option<String>, String> {
+        let mut raw = lightcraft_raw::decode(bytes).map_err(|e| e.to_string())?;
+        // colour only: geometric lens corrections would stop the sensor proxy from binning
+        raw.opcodes.list3.retain(|op| !op.is_lens_correction());
+        let Some(model) = raw.metadata.model.as_deref().map(str::trim).filter(|m| !m.is_empty()) else { return Ok(None) };
+        let Some(pairs) = crate::camera_preview::profile_pairs(&raw, bytes) else { return Ok(None) };
+        let step = pairs.len().div_ceil(PAIRS_PER_FILE).max(1);
+        let entry = self.models.entry(model.to_owned()).or_default();
+        entry.0 += 1;
+        entry.1.extend(pairs.into_iter().step_by(step));
+        Ok(Some(model.to_owned()))
+    }
+
+    /// Fit a profile per model with at least `min_files` photos.
+    pub fn fit(&self, min_files: usize) -> Vec<Result<CameraProfile, String>> {
+        let mut models: Vec<_> = self.models.iter().collect();
+        models.sort_by(|a, b| a.0.cmp(b.0));
+        models
+            .into_iter()
+            .filter(|(_, (files, _))| *files >= min_files)
+            .map(|(model, (files, pairs))| {
+                let (matrix, hue_sat) = crate::camera_preview::fit_profile(pairs).ok_or_else(|| format!("{model}: no usable colour fit"))?;
+                Ok(CameraProfile::new(model, *files, pairs.len(), matrix, hue_sat))
+            })
+            .collect()
+    }
+
+    /// Add another pool's photos and pairs (pools filled on separate threads).
+    pub fn merge(&mut self, other: Pool) {
+        for (model, (files, pairs)) in other.models {
+            let entry = self.models.entry(model).or_default();
+            entry.0 += files;
+            entry.1.extend(pairs);
+        }
+    }
+
+    /// Photos read per model.
+    pub fn files(&self) -> Vec<(String, usize)> {
+        let mut v: Vec<_> = self.models.iter().map(|(m, (n, _))| (m.clone(), *n)).collect();
+        v.sort();
+        v
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn profile() -> CameraProfile {
+        let table = HsvTable { hue_divisions: 4, sat_divisions: 2, val_divisions: 1, data: vec![[5.0, 1.2, 1.0]; 8], srgb_value: false };
+        CameraProfile::new("ILCE-7M4", 12, 3456, Mat3([[1.6, -0.5, -0.1], [-0.2, 1.3, -0.1], [-0.1, -0.2, 1.3]]), Some(table))
+    }
+
+    #[test]
+    fn profiles_round_trip_and_reject_bad_files() {
+        let dir = std::env::temp_dir().join(format!("lc-camera-profiles-{}", std::process::id()));
+        let path = save(&profile(), &dir).unwrap();
+        assert_eq!(path.file_name().unwrap(), "ILCE-7M4.json");
+        assert_eq!(load(&path).unwrap(), profile());
+        let bad = |p: CameraProfile| {
+            let path = dir.join("bad.json");
+            std::fs::write(&path, serde_json::to_vec(&p).unwrap()).unwrap();
+            load(&path).is_err()
+        };
+        let mut p = profile();
+        p.matrix[0][0] = f64::NAN;
+        assert!(bad(p), "non-finite matrix");
+        let mut p = profile();
+        p.matrix = [[0.0; 3]; 3];
+        assert!(bad(p), "singular matrix");
+        let mut p = profile();
+        if let Some(t) = p.hue_sat.as_mut() {
+            t.data.truncate(3);
+        }
+        assert!(bad(p), "table data doesn't match its shape");
+        let mut p = profile();
+        p.version = 99;
+        assert!(bad(p), "unknown version");
+        std::fs::write(dir.join("junk.json"), b"{not json").unwrap();
+        assert!(load(&dir.join("junk.json")).is_err());
+        assert!(load(&dir.join("missing.json")).is_err());
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+
+    #[test]
+    fn bundled_profiles_are_valid_and_named_after_their_model() {
+        assert!(!BUNDLED.is_empty());
+        for (model, json) in BUNDLED {
+            let p = parse(json.as_bytes(), model).unwrap();
+            assert_eq!(p.model, *model);
+            assert!(p.files >= 5 && p.hue_sat.is_some(), "{model}: {} photos", p.files);
+            assert_eq!(bundled(model), Some(p));
+        }
+        assert!(bundled("No Such Camera").is_none());
+    }
+
+    #[test]
+    fn file_names_are_safe() {
+        assert_eq!(file_name("ILCE-7M4"), "ILCE-7M4.json");
+        assert_eq!(file_name(" DSC-RX100M3 "), "DSC-RX100M3.json");
+        assert_eq!(file_name("../../etc/passwd"), "______etc_passwd.json");
+        assert_eq!(file_name("Ω 1/2"), "__1_2.json");
+    }
+
+    #[test]
+    fn pool_skips_files_that_cannot_contribute() {
+        let mut pool = Pool::default();
+        assert!(pool.add(b"not a raw file").is_err());
+        assert!(pool.fit(1).is_empty());
+        assert!(pool.files().is_empty());
+    }
+}
@@ -251,6 +251,9 @@ pub(crate) fn rename_folder_on_disk(from: &str, to: &str) -> std::result::Result

 /// After a folder moved from `from` to `to`: a browsed folder at or below it follows.
 pub(crate) fn follow_folder(s: &mut Session, from: &str, to: &str) {
+    // a library folder chosen at or below it follows too, as a source or as a filter
+    follow_library_folder(&mut s.library_folder, from, to);
+    follow_library_folder(&mut s.filter.library_folder, from, to);
    if let Some(b) = &mut s.browse
        && let Ok(rel) = Path::new(&b.path).strip_prefix(from)
    {
@@ -260,6 +263,17 @@ pub(crate) fn follow_folder(s: &mut Session, from: &str, to: &str) {
    }
 }

+/// A chosen library folder at or below `from` becomes the same place below `to`. Compared the
+/// way the filter does, by folder identity, so a differently spelled choice is not widened to
+/// the folder itself.
+fn follow_library_folder(chosen: &mut Option<String>, from: &str, to: &str) {
+    let Some(c) = chosen.as_deref() else { return };
+    if let Some(rest) = lightcraft_catalog::query::folder_rest(c, from) {
+        // joined by the platform, so the result is spelled like `to` and like a path read from disk
+        *chosen = Some(rest.iter().fold(std::path::PathBuf::from(to), |p, name| p.join(name)).to_string_lossy().to_string());
+    }
+}
+
 /// Rename or move a folder on disk (everything in it goes along, sidecars included) and relink
 /// the photos inside, as one undo step: undo renames the folder back and restores the photos'
 /// paths, redo repeats the move — each refused (and reported) when the destination is taken.
@@ -26,7 +26,7 @@ const PROBE_EDGE: usize = 384;
 pub(crate) fn probe(s: &mut Session, c: &str, x: f64, y: f64, neutral: impl FnOnce(&mut DevelopSettings)) -> Result<[f32; 3]> {
    let id = s.active().ok_or_else(|| bad(c, "no active photo"))?;
    let src = s.source_now(id, SourceLevel::Thumb).map_err(|e| bad(c, e))?;
-    let info = s.catalog.photo(id).map(|p| crate::media::source_info(p)).unwrap_or_default();
+    let info = s.source_info(id);
    let mut d = (*s.develop_of(id).unwrap_or_default()).clone();
    neutral(&mut d);
    let req = lightcraft_pipeline::RenderRequest::fit(PROBE_EDGE, PROBE_EDGE);
@@ -26,7 +26,12 @@ fn dng_names(path: &str) -> impl Iterator<Item = std::path::PathBuf> {
 /// written to a temp file, synced, read back identical and only then given its name — never
 /// replacing an existing file. On any failure no DNG is left behind and the raw stays in use.
 pub(crate) fn write_dng_for(s: &Session, path: &str, packet: String) -> std::result::Result<String, String> {
-    let bytes = match &s.media.file_bytes {
+    write_dng_with(s.media.file_bytes.as_ref(), path, packet)
+}
+
+/// [`write_dng_for`] without the session (imports convert on a worker thread).
+pub(crate) fn write_dng_with(file_bytes: Option<&crate::merge::ByteReader>, path: &str, packet: String) -> std::result::Result<String, String> {
+    let bytes = match file_bytes {
        Some(r) => r(path)?,
        None => std::fs::read(path).map_err(|e| format!("{path}: {e}"))?,
    };
@@ -144,7 +149,8 @@ fn edit_external(s: &mut Session, p: &Value) -> Result<Value> {
    };
    let mut written = Vec::new();
    let mut write = |path: &str, bytes: &[u8]| -> std::result::Result<(), String> {
-        crate::export::write_file(path, bytes)?;
+        // durable: the TIFF becomes a library photo the external editor then changes
+        crate::export::write_file_durable(path, bytes)?;
        written.push(path.to_string());
        Ok(())
    };
@@ -177,6 +183,33 @@ pub(crate) fn content_op(id: lightcraft_catalog::PhotoId, ph: &lightcraft_catalo
    })
 }

+/// Ops that fill a photo's empty camera fields (camera, lens, exposure, GPS, capture time) from a fresh probe.
+fn fill_missing_meta(id: lightcraft_catalog::PhotoId, ph: &lightcraft_catalog::Photo, info: &crate::media::ProbeInfo) -> Vec<Op> {
+    let (mut m, src) = (ph.meta.clone(), &info.meta);
+    let before = m.clone();
+    if m.camera.is_empty() {
+        m.camera = src.camera.clone();
+    }
+    if m.lens.is_empty() {
+        m.lens = src.lens.clone();
+    }
+    if m.shutter.is_empty() {
+        m.shutter = src.shutter.clone();
+    }
+    m.focal_mm = m.focal_mm.or(src.focal_mm);
+    m.aperture = m.aperture.or(src.aperture);
+    m.iso = m.iso.or(src.iso);
+    m.gps = m.gps.or(src.gps);
+    let mut ops = Vec::new();
+    if m != before {
+        ops.push(Op::SetMeta { id, meta: Box::new(m) });
+    }
+    if ph.captured.is_none() && info.captured.is_some() {
+        ops.push(Op::SetCaptured { id, captured: info.captured.clone() });
+    }
+    ops
+}
+
 /// Re-read photos whose files changed on disk (an external editor saved them): new size,
 /// dimensions and content hash, cached sources dropped. → {reloaded: [ids]}
 fn reload(s: &mut Session, p: &Value) -> Result<Value> {
@@ -193,8 +226,18 @@ fn reload(s: &mut Session, p: &Value) -> Result<Value> {
    let mut reloaded = Vec::new();
    for ((id, _), info) in paths.into_iter().zip(probed) {
        let (Ok(info), Some(ph)) = (info, s.catalog.photo(id)) else { continue };
-        let Some(op) = content_op(id, ph, info.clone()) else { continue };
+        // camera fields the catalog lacks (e.g. a raw imported before its format was read) are filled in;
+        // nothing already set is overwritten
+        let meta_ops = fill_missing_meta(id, ph, &info);
+        let Some(op) = content_op(id, ph, info.clone()) else {
+            if !meta_ops.is_empty() {
+                ops.extend(meta_ops);
+                reloaded.push(id);
+            }
+            continue;
+        };
        ops.push(op);
+        ops.extend(meta_ops);
        // virtual copies share the file
        for c in s.catalog.photos().filter(|c| c.copy_of == Some(id)) {
            ops.extend(content_op(c.id, c, info.clone()));
@@ -271,9 +314,9 @@ pub fn edit_specs() -> Vec<CommandSpec> {
        cmd!(
            "photo.reload",
            "Reload from Disk",
-            [],
+            ["Photo"],
            None,
-            "{ids?} — re-read photos whose files changed on disk (e.g. saved by an external editor), or raws shown from their embedded preview that can be decoded now → {reloaded}",
+            "{ids?} — re-read photos whose files changed on disk (e.g. saved by an external editor), or raws shown from their embedded preview that can be decoded now; camera fields the catalog lacks are filled in → {reloaded}",
            has_selection,
            reload
        ),
@@ -288,3 +331,32 @@ pub fn edit_specs() -> Vec<CommandSpec> {
        ),
    ]
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use lightcraft_catalog::{Photo, PhotoId, Source};
+
+    /// Reload fills camera fields a photo lacks (a CR3 imported before CR3 metadata was read) and keeps
+    /// everything already set.
+    #[test]
+    fn reload_fills_only_missing_camera_fields() {
+        let mut ph = Photo::new(PhotoId(1), Source::File { path: "/x.cr3".into() }, "x.cr3", "CR3", 1620, 1080, "2026-10-06T00:00:00");
+        ph.meta.title = "Mine".into();
+        ph.meta.iso = Some(800);
+        let mut info = crate::media::ProbeInfo { captured: Some("2026-10-04T08:16:11".into()), ..Default::default() };
+        info.meta.camera = "Canon EOS R6 Mark III".into();
+        info.meta.lens = "RF24-105mm".into();
+        info.meta.iso = Some(400);
+        info.meta.aperture = Some(6.3);
+        let ops = fill_missing_meta(PhotoId(1), &ph, &info);
+        let Some(Op::SetMeta { meta, .. }) = ops.first() else { panic!("{ops:?}") };
+        assert_eq!((meta.camera.as_str(), meta.lens.as_str(), meta.aperture), ("Canon EOS R6 Mark III", "RF24-105mm", Some(6.3)));
+        assert_eq!((meta.title.as_str(), meta.iso), ("Mine", Some(800)), "set fields are kept");
+        assert!(matches!(ops.get(1), Some(Op::SetCaptured { captured: Some(_), .. })));
+        // nothing missing → nothing to do
+        ph.meta = (**meta).clone();
+        ph.captured = Some("2026-10-04T08:16:11".into());
+        assert!(fill_missing_meta(PhotoId(1), &ph, &info).is_empty());
+    }
+}
@@ -2,7 +2,7 @@

 use lightcraft_catalog::{Op, PhotoId, Version};
 use lightcraft_develop::{DevelopSettings, Preset, Section, SettingsGroup, Treatment, Upright, WbMode, controls};
-use lightcraft_geom::{CropGeometry, Point, Rect, crop_fit_angle};
+use lightcraft_geom::{CropGeometry, CropHandle, Point, Rect, crop_fit_angle, drag_crop};
 use serde_json::{Value, json};

 use super::{CommandSpec, always, bad, bool_or, cmd, f64_or, f64_req, has_active, has_clipboard, has_selection, ok, str_param};
@@ -37,6 +37,32 @@ fn crop_dims(s: &Session, id: PhotoId) -> (f64, f64) {
    if o.swaps_axes() { (h, w) } else { (w, h) }
 }

+/// `v` as a list of numbers; `None` unless it is an array of nothing but numbers.
+fn numbers(v: Option<&Value>) -> Option<Vec<f64>> {
+    v?.as_array()?.iter().map(Value::as_f64).collect()
+}
+
+/// A width × height lock stored as hundredths. Rejects non-finite, non-positive and
+/// extreme (beyond 20:1) shapes, which would give an empty or unusable crop.
+fn aspect_tuple(c: &str, x: f64, y: f64) -> Result<(u32, u32)> {
+    let ratio = x / y;
+    if !(x.is_finite()
+        && y.is_finite()
+        && x > 0.0
+        && y > 0.0
+        && ratio.is_finite()
+        && (1.0 / lightcraft_geom::MAX_RATIO..=lightcraft_geom::MAX_RATIO).contains(&ratio))
+    {
+        return Err(bad(c, "aspect needs two positive numbers with a ratio between 1:20 and 20:1"));
+    }
+    let to = |v: f64| (v * 100.0).round();
+    let (a, b) = (to(x), to(y));
+    if a < 1.0 || b < 1.0 || a > f64::from(u32::MAX) || b > f64::from(u32::MAX) {
+        return Err(bad(c, "aspect numbers are out of range"));
+    }
+    Ok((a as u32, b as u32))
+}
+
 fn set_aspect(d: &mut DevelopSettings, w: f64, h: f64, aspect: Option<(u32, u32)>) {
    d.crop.aspect = aspect;
    let a = aspect.map(|(aw, ah)| {
@@ -98,7 +124,11 @@ pub fn specs() -> Vec<CommandSpec> {
                    }
                }
                let label = if vals.len() == 1 { controls::find(&vals[0].0).map(|c| c.label).unwrap_or("Edit").to_string() } else { "Edit".into() };
-                let apply = |d: &mut DevelopSettings| {
+                let apply = |d: &mut DevelopSettings, info: &lightcraft_pipeline::SourceInfo| {
+                    if d.wb.mode == WbMode::AsShot && vals.iter().any(|(k, _)| k == "wb.temp" || k == "wb.tint") {
+                        d.wb.temp = info.as_shot_temp;
+                        d.wb.tint = info.as_shot_tint;
+                    }
                    for (k, v) in &vals {
                        controls::set(d, k, *v);
                        if k == "wb.temp" || k == "wb.tint" {
@@ -113,15 +143,18 @@ pub fn specs() -> Vec<CommandSpec> {
                        .filter_map(|id| s.develop_of(*id).map(|d| (*id, d)))
                        .filter_map(|(id, d)| {
                            let mut d = (*d).clone();
-                            apply(&mut d);
+                            let info = s.source_info(id);
+                            apply(&mut d, &info);
                            s.develop_op(id, d, &label)
                        })
                        .collect();
                    s.commit(&label, Op::Batch { ops })?;
                    return ok();
                }
+                let id = active(s, "develop.set")?;
+                let info = s.source_info(id);
                edit(s, "develop.set", &label, |d| {
-                    apply(d);
+                    apply(d, &info);
                    Ok(())
                })
            }
@@ -130,7 +163,15 @@ pub fn specs() -> Vec<CommandSpec> {
            let c = str_param(p, "control").ok_or_else(|| bad("develop.adjust", "missing control"))?.to_string();
            let spec = controls::find(&c).ok_or_else(|| bad("develop.adjust", "unknown control"))?;
            let delta = f64_req(p, "delta", "develop.adjust")?;
+            let info = s.source_info(active(s, "develop.adjust")?);
            edit(s, "develop.adjust", spec.label, |d| {
+                if c == "wb.temp" || c == "wb.tint" {
+                    if d.wb.mode == WbMode::AsShot {
+                        d.wb.temp = info.as_shot_temp;
+                        d.wb.tint = info.as_shot_tint;
+                    }
+                    d.wb.mode = WbMode::Custom;
+                }
                let v = controls::get(d, &c).unwrap_or(spec.default);
                controls::set(d, &c, v + delta);
                Ok(())
@@ -149,12 +190,18 @@ pub fn specs() -> Vec<CommandSpec> {
            let ops = ids
                .iter()
                .filter_map(|id| s.develop_of(*id).map(|d| (*id, d)))
-                .filter_map(|(id, d)| {
+                .filter_map(|(id, _d)| {
                    // back to the photo's import defaults when a default preset gave it its look
                    let look = s.catalog.photo(id).and_then(|p| p.import_look.clone());
                    let fresh = match look {
                        Some(l) => (*l).clone(),
-                        None => DevelopSettings { wb: lightcraft_develop::WhiteBalance { mode: WbMode::AsShot, ..d.wb }, ..Default::default() },
+                        None => {
+                            let info = s.source_info(id);
+                            DevelopSettings {
+                                wb: lightcraft_develop::WhiteBalance { mode: WbMode::AsShot, temp: info.as_shot_temp, tint: info.as_shot_tint },
+                                ..Default::default()
+                            }
+                        }
                    };
                    s.develop_op(id, fresh, "Reset")
                })
@@ -203,7 +250,7 @@ pub fn specs() -> Vec<CommandSpec> {
            |s, _| {
                let id = active(s, "develop.autoBwMix")?;
                let src = s.source_now(id, SourceLevel::Thumb).map_err(|e| bad("develop.autoBwMix", e))?;
-                let info = s.catalog.photo(id).map(|p| crate::media::source_info(p)).unwrap_or_default();
+                let info = s.source_info(id);
                let d = s.develop_of(id).unwrap_or_default();
                let m = lightcraft_pipeline::auto::auto_bw_mix(&src, &info, &d);
                edit(s, "develop.autoBwMix", "Auto B&W Mix", |d| {
@@ -218,7 +265,7 @@ pub fn specs() -> Vec<CommandSpec> {
        cmd!("develop.auto", "Auto Settings", ["Photo"], Some("Shift+A"), "{}", has_active, |s, _| {
            let id = active(s, "develop.auto")?;
            let src = s.source_now(id, SourceLevel::Thumb).map_err(|e| bad("develop.auto", e))?;
-            let info = s.catalog.photo(id).map(|p| crate::media::source_info(p)).unwrap_or_default();
+            let info = s.source_info(id);
            let d = s.develop_of(id).unwrap_or_default();
            let a = lightcraft_pipeline::auto::auto_tone(&src, &info, &d);
            edit(s, "develop.auto", "Auto", |d| {
@@ -245,7 +292,7 @@ pub fn specs() -> Vec<CommandSpec> {
                let mode: WbMode =
                    serde_json::from_value(p.get("mode").cloned().unwrap_or(json!("custom"))).map_err(|e| bad("develop.wb", e.to_string()))?;
                let id = active(s, "develop.wb")?;
-                let info = s.catalog.photo(id).map(|p| crate::media::source_info(p)).unwrap_or_default();
+                let info = s.source_info(id);
                let (mut t, mut tint) = match mode {
                    WbMode::AsShot => (info.as_shot_temp, info.as_shot_tint),
                    WbMode::Auto => {
@@ -256,7 +303,7 @@ pub fn specs() -> Vec<CommandSpec> {
                        .preset()
                        .map(|(t, ti)| {
                            // presets are relative to daylight for rendered files
-                            if info.raw { (t, ti) } else { (6500.0 * t / 5500.0, ti) }
+                            if info.raw && !info.relative_wb { (t, ti) } else { (6500.0 * t / 5500.0, ti) }
                        })
                        .unwrap_or((info.as_shot_temp, info.as_shot_tint)),
                };
@@ -277,7 +324,7 @@ pub fn specs() -> Vec<CommandSpec> {
            let (x, y) = (f64_req(p, "x", "develop.wbPick")?, f64_req(p, "y", "develop.wbPick")?);
            let id = active(s, "develop.wbPick")?;
            let src = s.source_now(id, SourceLevel::Thumb).map_err(|e| bad("develop.wbPick", e))?;
-            let info = s.catalog.photo(id).map(|p| crate::media::source_info(p)).unwrap_or_default();
+            let info = s.source_info(id);
            let d = s.develop_of(id).unwrap_or_default();
            // Sample a small neighbourhood in the oriented source.
            let o = src.oriented(d.orientation);
@@ -374,6 +421,46 @@ pub fn specs() -> Vec<CommandSpec> {
                Ok(())
            })
        }),
+        cmd!(
+            "crop.drag",
+            "Drag Crop Handle",
+            [],
+            None,
+            "{handle: topLeft|topRight|bottomRight|bottomLeft|top|right|bottom|left|move | 0..8, from: [x,y], to: [x,y] (normalized, straightened frame), start?: [x0,y0,x1,y1] (default: the current crop)} — drags a crop handle; stops at the image edge, keeps the opposite edges, honours the aspect lock",
+            has_active,
+            |s, p| {
+                let id = active(s, "crop.drag")?;
+                let (w, h) = crop_dims(s, id);
+                let handle = match p.get("handle") {
+                    Some(Value::String(n)) => CropHandle::from_name(n),
+                    Some(v) => v.as_u64().and_then(|i| u8::try_from(i).ok()).and_then(CropHandle::from_index),
+                    None => None,
+                }
+                .ok_or_else(|| bad("crop.drag", "unknown handle"))?;
+                let point = |k: &str| -> Result<Point> {
+                    match numbers(p.get(k)).as_deref() {
+                        Some([x, y]) if x.is_finite() && y.is_finite() => Ok(Point::new(*x, *y)),
+                        _ => Err(bad("crop.drag", format!("`{k}` needs [x, y]"))),
+                    }
+                };
+                let (from, to) = (point("from")?, point("to")?);
+                let given = match (p.get("start"), numbers(p.get("start")).as_deref()) {
+                    (None | Some(Value::Null), _) => None,
+                    (_, Some(&[x0, y0, x1, y1])) if [x0, y0, x1, y1].iter().all(|v| v.is_finite()) => {
+                        Some(Rect::new(x0.min(x1), y0.min(y1), x0.max(x1), y0.max(y1)))
+                    }
+                    _ => return Err(bad("crop.drag", "`start` needs 4 numbers")),
+                };
+                edit(s, "crop.drag", "Crop", |d| {
+                    let start = CropGeometry { rect: given.unwrap_or(d.crop.geometry.rect), angle: d.crop.geometry.angle };
+                    // A locked crop keeps the shape it has: the lock stores a width:height tuple whose
+                    // orientation is reinterpreted per image, so the frame itself is the truth.
+                    let ratio = d.crop.aspect.and(Some(start.rect_px(w, h).aspect())).filter(|a| a.is_finite() && *a > 0.0);
+                    d.crop.geometry = drag_crop(start, handle, from, to, w, h, ratio);
+                    Ok(())
+                })
+            }
+        ),
        cmd!(
            "crop.straighten",
            "Straighten",
@@ -405,7 +492,7 @@ pub fn specs() -> Vec<CommandSpec> {
            |s, _| {
                let id = active(s, "crop.autoStraighten")?;
                let src = s.source_now(id, SourceLevel::Preview).map_err(|e| bad("crop.autoStraighten", e))?;
-                let info = s.catalog.photo(id).map(|p| crate::media::source_info(p)).unwrap_or_default();
+                let info = s.source_info(id);
                let d = s.develop_of(id).unwrap_or_default();
                let Some(level) = lightcraft_pipeline::upright::level_degrees(&src, &info, &d) else {
                    return Ok(json!({"changed": false, "reason": "no dominant horizontal or vertical lines"}));
@@ -449,11 +536,12 @@ pub fn specs() -> Vec<CommandSpec> {
                        let (x, y) = a.split_once('x').ok_or_else(|| bad("crop.aspect", "use WxH"))?;
                        let (x, y): (f64, f64) =
                            (x.parse().map_err(|_| bad("crop.aspect", "bad number"))?, y.parse().map_err(|_| bad("crop.aspect", "bad number"))?);
-                        Some(((x * 100.0) as u32, (y * 100.0) as u32))
-                    }
-                    Some(Value::Array(a)) if a.len() == 2 => {
-                        Some(((a[0].as_f64().unwrap_or(1.0) * 100.0) as u32, (a[1].as_f64().unwrap_or(1.0) * 100.0) as u32))
+                        Some(aspect_tuple("crop.aspect", x, y)?)
                    }
+                    Some(v @ Value::Array(_)) => match numbers(Some(v)).as_deref() {
+                        Some(&[x, y]) => Some(aspect_tuple("crop.aspect", x, y)?),
+                        _ => return Err(bad("crop.aspect", "use [w, h] with two numbers")),
+                    },
                    _ => return Err(bad("crop.aspect", "missing aspect")),
                };
                edit(s, "crop.aspect", "Crop Aspect", |d| {
@@ -501,7 +589,7 @@ pub fn specs() -> Vec<CommandSpec> {
                    Upright::Off | Upright::Guided => None,
                    m => {
                        let src = s.source_now(id, SourceLevel::Preview).map_err(|e| bad("geometry.upright", e))?;
-                        let info = s.catalog.photo(id).map(|p| crate::media::source_info(p)).unwrap_or_default();
+                        let info = s.source_info(id);
                        Some(lightcraft_pipeline::upright::auto_transform(&src, &info, &d, m))
                    }
                };
@@ -657,6 +745,11 @@ pub fn specs() -> Vec<CommandSpec> {
                    .filter_map(|id| s.develop_of(id).map(|d| (id, d)))
                    .filter_map(|(id, d)| {
                        let mut nd = (*d).clone();
+                        if nd.wb.mode == WbMode::AsShot && (ctl == "wb.temp" || ctl == "wb.tint") {
+                            let info = s.source_info(id);
+                            nd.wb.temp = info.as_shot_temp;
+                            nd.wb.tint = info.as_shot_tint;
+                        }
                        let v = controls::get(&nd, &ctl).unwrap_or(spec.default);
                        controls::set(&mut nd, &ctl, v + delta);
                        if ctl == "wb.temp" || ctl == "wb.tint" {
@@ -23,7 +23,8 @@ impl Session {
            .into_iter()
            .find(|(x, _)| x.name.eq_ignore_ascii_case(name.trim()))
            .ok_or_else(|| format!("unknown export preset `{name}` (see export.presets)"))?;
-        let mut out = preset.params;
+        // a preset saved by another version may hold keys this one doesn't know: not the caller's typo
+        let mut out = crate::export::ExportOptions::known_keys_only(&preset.params);
        if let (Some(o), Some(own)) = (out.as_object_mut(), p.as_object()) {
            for (k, v) in own.iter().filter(|(k, _)| *k != "preset") {
                o.insert(k.clone(), v.clone());
@@ -54,6 +55,8 @@ fn save(s: &mut Session, p: &Value) -> Result<Value> {
    if let Some(o) = params.as_object_mut() {
        o.retain(|k, _| !NOT_SETTINGS.contains(&k.as_str()));
    }
+    // a preset that app.export would refuse is refused here, where the typo is on screen
+    crate::export::ExportOptions::validate(ID, &params)?;
    let preset = ExportPreset { name: name.to_string(), params };
    match s.export_presets.iter_mut().find(|x| x.name.eq_ignore_ascii_case(name)) {
        Some(x) => *x = preset,
@@ -1,12 +1,120 @@
 //! Library commands: view source, filter/sort, selection, ratings/flags/labels, rotate, delete,
 //! metadata, albums, import.

-use lightcraft_catalog::{Album, AlbumId, ColorLabel, CopyrightStatus, Flag, GroupBy, Op, PhotoId, Sort, SortKey};
+use lightcraft_catalog::{Album, AlbumId, ColorLabel, CopyrightStatus, Filter, Flag, GroupBy, Op, PhotoId, Sort, SortKey};
 use serde_json::{Value, json};

 use super::{CommandSpec, always, bad, bool_or, cmd, has_active, has_selection, ok, str_param};
 use crate::{LibrarySource, Result, Selection, Session};

+/// The auto-import folder's visible files with their sizes (the file-system half of
+/// `library.autoImportScan`; the app lists on a worker thread and passes `listing`).
+pub fn list_auto_import_folder(folder: &str) -> std::result::Result<Vec<(String, u64)>, String> {
+    let rd = std::fs::read_dir(folder).map_err(|e| format!("{folder}: {e}"))?;
+    Ok(rd
+        .flatten()
+        .filter(|e| !e.file_name().to_string_lossy().starts_with('.'))
+        .filter_map(|e| {
+            let m = std::fs::metadata(e.path()).ok()?;
+            m.is_file().then(|| (e.path().to_string_lossy().to_string(), m.len()))
+        })
+        .collect())
+}
+
+/// `library.import`'s params, checked (no file-system calls).
+pub struct ImportRequest {
+    pub paths: Vec<String>,
+    pub opts: crate::import::ImportOptions,
+    pub album: Option<u64>,
+    pub album_name: Option<String>,
+}
+
+/// Parse and check `library.import`'s params (the app's import task runs the import itself, on a
+/// worker thread, with the same options).
+pub fn import_params(s: &Session, p: &Value) -> Result<ImportRequest> {
+    let paths = strs(p, "paths");
+    let mode = match str_param(p, "mode").unwrap_or("add") {
+        "add" => crate::import::ImportMode::Add,
+        "copy" => crate::import::ImportMode::Copy,
+        "move" => crate::import::ImportMode::Move,
+        other => return Err(bad("library.import", format!("unknown mode `{other}` (add|copy|move)"))),
+    };
+    let preset = match str_param(p, "preset").filter(|x| !x.is_empty()) {
+        Some(id) => Some(s.presets.iter().find(|x| x.id == id).cloned().ok_or_else(|| bad("library.import", format!("unknown preset `{id}`")))?),
+        None => None,
+    };
+    let album = p.get("album").and_then(Value::as_u64);
+    if let Some(a) = album
+        && s.catalog.album(AlbumId(a)).is_none_or(|al| al.folder || al.is_smart())
+    {
+        return Err(bad("library.import", "album must be a regular album"));
+    }
+    let organize = match str_param(p, "organize") {
+        Some(o) => crate::import::Organize::parse(o).ok_or_else(|| {
+            bad("library.import", format!("unknown organize `{o}` (date|month|flat, or a folder template like {{date:%Y}}/{{date:%Y%m%d}})"))
+        })?,
+        None => Default::default(),
+    };
+    if let crate::import::Organize::Template(t) = &organize
+        && let Some(e) = crate::rename::folder_template_error(t)
+    {
+        return Err(bad("library.import", e));
+    }
+    let metadata_preset = str_param(p, "metadataPreset").map(str::trim).filter(|n| !n.is_empty()).map(str::to_string);
+    if let Some(n) = &metadata_preset
+        && !s.metadata_presets.iter().any(|m| m.name.eq_ignore_ascii_case(n))
+    {
+        return Err(bad("library.import", format!("unknown metadata preset `{n}`")));
+    }
+    let on_deleted = match str_param(p, "onDeleted") {
+        Some(v) => {
+            crate::import::OnDeleted::parse(v).ok_or_else(|| bad("library.import", format!("unknown onDeleted `{v}` (skip|restore|fresh)")))?
+        }
+        None => Default::default(),
+    };
+    let opts = crate::import::ImportOptions {
+        on_deleted,
+        mode,
+        preset,
+        keywords: strs(p, "keywords"),
+        destination: str_param(p, "destination").map(str::to_string),
+        organize,
+        rename: str_param(p, "rename").map(str::to_string),
+        rename_start: p.get("renameStart").and_then(Value::as_u64).unwrap_or(1) as usize,
+        metadata_preset,
+        convert_dng: bool_or(p, "dng", false),
+        local: bool_or(p, "local", false),
+    };
+    let album_name = str_param(p, "albumName").map(str::trim).filter(|n| !n.is_empty()).map(str::to_string);
+    Ok(ImportRequest { paths, opts, album, album_name })
+}
+
+/// After a batch of an import was committed: the album (a new one named `album_name` when there
+/// is no `album` and something was imported) gets the photos. Returns the report as JSON (with
+/// `album`).
+pub fn import_batch_done(s: &mut Session, report: crate::import::ImportReport, mut album: Option<u64>, album_name: Option<&str>) -> Result<Value> {
+    let mut report = serde_json::to_value(report).unwrap_or_default();
+    // photos an import restored from Recently Deleted take part like new ones (album, selection)
+    let imported: Vec<u64> =
+        ["imported", "restored"].iter().flat_map(|k| report[*k].as_array().into_iter().flatten().filter_map(Value::as_u64)).collect();
+    if album.is_none()
+        && let Some(name) = album_name
+        && !imported.is_empty()
+    {
+        let r = s.execute("album.create", &json!({"name": name}))?;
+        album = r["id"].as_u64();
+    }
+    if let Some(a) = album
+        && !imported.is_empty()
+    {
+        // (album.addPhotos wants a selection: the new photos are about to be it)
+        s.selection = Selection::single(PhotoId(imported[0]));
+        s.execute("album.addPhotos", &json!({"id": a, "ids": imported}))?;
+        report["album"] = json!(a);
+    }
+    Ok(report)
+}
+
 fn album_param(p: &Value, key: &str, c: &str) -> Result<AlbumId> {
    p.get(key).and_then(Value::as_u64).map(AlbumId).ok_or_else(|| bad(c, format!("missing album `{key}`")))
 }
@@ -125,6 +233,25 @@ fn select_by(s: &mut Session, p: &Value) -> Result<Value> {
    Ok(json!({"selected": n}))
 }

+/// Seeds stay exactly representable as a JSON double, so web and agent clients read back what they wrote.
+const MAX_SEED: u64 = 1 << 53;
+
+/// `seed` as an integer in `0..2^53`, or `default` when absent or null; anything else is an error.
+fn seed_param(p: &Value, cmd: &str, default: u64) -> Result<u64> {
+    match p.get("seed") {
+        None | Some(Value::Null) => Ok(default),
+        Some(v) => v.as_u64().filter(|n| *n < MAX_SEED).ok_or_else(|| bad(cmd, "seed must be an integer from 0 to 2^53 - 1")),
+    }
+}
+
+/// The seed after `prev` at time `now`: a mix of `prev` and the clock text, so repeated reshuffles
+/// within one clock tick still differ (barring a 2^-53 collision). Kept below 2^53 so JSON
+/// clients that read numbers as doubles (web, MCP agents) get the same seed back.
+fn next_seed(prev: u64, now: &str) -> u64 {
+    let t = now.bytes().fold(0u64, |h, b| lightcraft_catalog::mix64(h ^ u64::from(b)));
+    (lightcraft_catalog::mix64(prev.wrapping_add(1)) ^ t) & (MAX_SEED - 1)
+}
+
 pub fn specs() -> Vec<CommandSpec> {
    vec![
        // ---- view source / filter / sort
@@ -133,7 +260,7 @@ pub fn specs() -> Vec<CommandSpec> {
            "Show Source",
            [],
            None,
-            "{kind: all|recentlyAdded|album|recentlyDeleted|picks|missing, id?: albumId}",
+            "{kind: all|recentlyAdded|album|recentlyDeleted|picks|missing|libraryFolder, id?: albumId, path?: a path from library.folders (for libraryFolder)}",
            always,
            |s, p| {
                let kind = str_param(p, "kind").unwrap_or("all");
@@ -150,6 +277,25 @@ pub fn specs() -> Vec<CommandSpec> {
                        }
                        LibrarySource::Album(a)
                    }
+                    "libraryFolder" => {
+                        let path = str_param(p, "path").filter(|d| !d.trim().is_empty() && !lightcraft_catalog::query::folder_key(d).is_empty());
+                        let path = path.ok_or_else(|| bad("library.source", "libraryFolder needs the `path` of a folder from library.folders"))?;
+                        if lightcraft_catalog::folders::is_startup_disk(path) {
+                            return Err(bad("library.source", "the startup disk's path covers every disk: choose a folder in it"));
+                        }
+                        let f = Filter { library_folder: Some(path.to_string()), ..Default::default() };
+                        let ids = s.catalog.query(&f, &Sort::default());
+                        if ids.is_empty() {
+                            return Err(bad("library.source", format!("{path}: no photo in the library was imported from it")));
+                        }
+                        if covers_other_disks(s, path, &ids) {
+                            return Err(bad("library.source", format!("{path} holds other disks as well: choose a disk or a folder on one")));
+                        }
+                        s.library_folder = Some(path.to_string());
+                        // one folder at a time: a folder filter left over would be ignored
+                        s.filter.library_folder = None;
+                        LibrarySource::LibraryFolder
+                    }
                    other => return Err(bad("library.source", format!("unknown source `{other}`"))),
                };
                let vis = s.visible_cloned();
@@ -164,15 +310,75 @@ pub fn specs() -> Vec<CommandSpec> {
            "Filter",
            [],
            None,
-            "partial Filter: {text?, rating?, ratingOp?: atLeast|exactly|atMost, flag?: pick|reject|none|null, label?, kind?, merged?: hdr|panorama|hdrPanorama|any, edited?, date?, keyword?, camera?}",
+            "partial Filter: {text?, rating?, ratingOp?: atLeast|exactly|atMost, flag?: pick|reject|none|null, label?, kind?, merged?: hdr|panorama|hdrPanorama|any, edited?, date?, libraryFolder?: a path from library.folders, keyword?, person?, camera?}",
            always,
            |s, p| {
                let mut v = serde_json::to_value(&s.filter).unwrap_or_default();
                lightcraft_develop::presets::deep_merge(&mut v, p);
-                s.filter = serde_json::from_value(v).map_err(|e| bad("library.filter", e.to_string()))?;
+                let f: Filter = serde_json::from_value(v).map_err(|e| bad("library.filter", e.to_string()))?;
+                let mut f = f;
+                // a blank folder is no folder: no hidden "filters active" state
+                f.library_folder = f.library_folder.filter(|d| !d.trim().is_empty());
+                if f.library_folder.is_some() && s.source == LibrarySource::LibraryFolder {
+                    return Err(bad("library.filter", "a folder is already shown (library.source): show another source first"));
+                }
+                s.filter = f;
                Ok(json!({"count": s.visible().len()}))
            }
        ),
+        cmd!(
+            query "library.folders",
+            "Library Folders",
+            [],
+            None,
+            "{} → [{name, path, count, own, volume, selectable, children}] the disks and the folders the library's photos were imported from, with photo counts (subfolders included in `count`); show one with library.source {kind: libraryFolder, path} (rows with selectable false only open)",
+            always,
+            |s, _| Ok(serde_json::to_value(s.catalog.folder_tree()).unwrap_or_default())
+        ),
+        cmd!(
+            "library.removeFolder",
+            "Remove Folder from Library",
+            [],
+            None,
+            "{path, disk?: bool} — move the library photos imported from this folder (and the folders inside it) to Recently Deleted; one undo step, no file is touched. A whole disk or share (`/Volumes/nas`, `C:\\`, `\\\\srv\\share`) goes only with `disk: true`, the startup disk never → {removed}",
+            always,
+            |s, p| {
+                const C: &str = "library.removeFolder";
+                let path = str_param(p, "path").filter(|d| !d.trim().is_empty()).ok_or_else(|| bad(C, "missing `path`"))?;
+                if lightcraft_catalog::query::folder_key(path).is_empty() {
+                    return Err(bad(C, format!("{path}: not a folder")));
+                }
+                if lightcraft_catalog::folders::is_startup_disk(path) {
+                    return Err(bad(C, "choose a folder, not the whole startup disk"));
+                }
+                if lightcraft_catalog::folders::is_disk_root(path) && !bool_or(p, "disk", false) {
+                    return Err(bad(C, format!("{path} is a whole disk or share: pass `disk: true` to remove everything on it")));
+                }
+                let f = Filter { library_folder: Some(path.to_string()), ..Default::default() };
+                let ids = s.catalog.query(&f, &Sort::default());
+                if ids.is_empty() {
+                    return Err(bad(C, format!("{path}: no photo in the library was imported from it")));
+                }
+                if covers_other_disks(s, path, &ids) && !bool_or(p, "disk", false) {
+                    return Err(bad(C, format!("{path} holds whole disks: pass `disk: true` to remove everything on them")));
+                }
+                let ops = ids.iter().map(|id| Op::SetDeleted { id: *id, deleted: true }).collect();
+                s.commit("Remove Folder from Library", Op::Batch { ops })?;
+                if s.filter.library_folder.as_deref().is_some_and(|c| lightcraft_catalog::query::folder_within(c, path)) {
+                    s.filter.library_folder = None;
+                }
+                // the folder being shown is gone: back to everything, as for a deleted album
+                if s.library_folder.as_deref().is_some_and(|c| lightcraft_catalog::query::folder_within(c, path)) {
+                    s.library_folder = None;
+                    if s.source == LibrarySource::LibraryFolder {
+                        s.source = LibrarySource::All;
+                    }
+                }
+                let vis = s.visible_cloned();
+                s.selection = vis.first().map(|f| Selection::single(*f)).unwrap_or_default();
+                Ok(json!({"removed": ids.len()}))
+            }
+        ),
        cmd!("library.clearFilter", "Clear Filters", ["View"], None, "{}", always, |s, _| {
            s.filter = Default::default();
            Ok(json!({"count": s.visible().len()}))
@@ -182,7 +388,7 @@ pub fn specs() -> Vec<CommandSpec> {
            "Sort",
            ["View", "Sort"],
            None,
-            "{key?: captureDate|importDate|editDate|fileName|rating|fileSize, ascending?: bool, group?: auto|none|day|month|year}",
+            "{key?: captureDate|importDate|editDate|fileName|rating|fileSize|random, ascending?: bool, group?: auto|none|day|month|year, seed?: u64 (the shuffle `random` gives)}",
            always,
            |s, p| {
                let key: SortKey = match p.get("key") {
@@ -193,7 +399,31 @@ pub fn specs() -> Vec<CommandSpec> {
                    Some(g) => GroupBy::parse(g).ok_or_else(|| bad("library.sort", "group must be auto|none|day|month|year"))?,
                    None => s.sort.group,
                };
-                s.sort = Sort { key, ascending: bool_or(p, "ascending", s.sort.ascending), group };
+                let mut seed = seed_param(p, "library.sort", s.sort.seed)?;
+                let explicit = p.get("seed").is_some_and(|v| !v.is_null());
+                if key == SortKey::Random && s.sort.key != SortKey::Random && !explicit {
+                    // switching to Random is a fresh shuffle, not whatever seed was left behind
+                    seed = next_seed(seed, &(s.clock)());
+                }
+                s.sort = Sort { key, ascending: bool_or(p, "ascending", s.sort.ascending), group, seed };
+                ok()
+            }
+        ),
+        cmd!(
+            "library.shuffle",
+            "Reshuffle",
+            ["View", "Sort"],
+            None,
+            "{seed?: 0..2^53-1} — sort at random; without `seed` a new shuffle each time",
+            always,
+            |s, p| {
+                let seed = match seed_param(p, "library.shuffle", s.sort.seed)? {
+                    given if p.get("seed").is_some_and(|v| !v.is_null()) => given,
+                    // derived from the previous seed and the session clock: reproducible under a test
+                    // clock, and no RNG needed
+                    prev => next_seed(prev, &(s.clock)()),
+                };
+                s.sort = Sort { key: SortKey::Random, seed, ..s.sort };
                ok()
            }
        ),
@@ -214,36 +444,50 @@ pub fn specs() -> Vec<CommandSpec> {
            }
        ),
        // ---- selection
-        cmd!("library.select", "Select Photos", [], None, "{ids: [id], active?: id, mode?: replace|add|toggle|range}", always, |s, p| {
-            let ids = ids_param(p).unwrap_or_default();
-            let mode = str_param(p, "mode").unwrap_or("replace");
-            s.end_interaction()?;
-            match mode {
-                "replace" => {
-                    s.selection =
-                        Selection { ids: ids.clone(), active: p.get("active").and_then(Value::as_u64).map(PhotoId).or(ids.first().copied()) };
+        cmd!(
+            "library.select",
+            "Select Photos",
+            [],
+            None,
+            "{ids: [id], active?: id, mode?: replace|add|toggle|range} — every id must be a photo of the library",
+            always,
+            |s, p| {
+                let ids = ids_param(p).unwrap_or_default();
+                let active = p.get("active").and_then(Value::as_u64).map(PhotoId);
+                let mode = str_param(p, "mode").unwrap_or("replace");
+                // An id that is not in the library is an error, and the selection stays as it was:
+                // selecting it would otherwise report success and leave the session with no usable
+                // active photo (#182).
+                if let Some(id) = ids.iter().chain(active.as_ref()).find(|id| s.catalog.photo(**id).is_none()) {
+                    return Err(bad("library.select", format!("no such photo {}", id.0)));
                }
-                "add" => {
-                    for id in ids {
-                        if !s.selection.contains(id) {
-                            s.selection.ids.push(id);
+                s.end_interaction()?;
+                match mode {
+                    "replace" => {
+                        s.selection = Selection { ids: ids.clone(), active: active.or(ids.first().copied()) };
+                    }
+                    "add" => {
+                        for id in ids {
+                            if !s.selection.contains(id) {
+                                s.selection.ids.push(id);
+                            }
+                            s.selection.active = Some(id);
                        }
-                        s.selection.active = Some(id);
                    }
-                }
-                "toggle" => ids.into_iter().for_each(|id| s.selection.toggle(id)),
-                "range" => {
-                    let vis = s.visible_cloned();
-                    if let Some(id) = ids.first() {
-                        s.selection.extend_to(*id, &vis);
+                    "toggle" => ids.into_iter().for_each(|id| s.selection.toggle(id)),
+                    "range" => {
+                        let vis = s.visible_cloned();
+                        if let Some(id) = ids.first() {
+                            s.selection.extend_to(*id, &vis);
+                        }
                    }
+                    other => return Err(bad("library.select", format!("unknown mode `{other}`"))),
                }
-                other => return Err(bad("library.select", format!("unknown mode `{other}`"))),
+                s.active_mask = None;
+                s.active_spot = None;
+                Ok(json!({"selected": s.selection.ids.len()}))
            }
-            s.active_mask = None;
-            s.active_spot = None;
-            Ok(json!({"selected": s.selection.ids.len()}))
-        }),
+        ),
        cmd!("library.selectAll", "Select All", ["Edit"], Some("Cmd+A"), "{}", always, |s, _| {
            let vis = s.visible_cloned();
            s.selection = Selection { active: s.selection.active.filter(|a| vis.contains(a)).or(vis.first().copied()), ids: vis };
@@ -347,6 +591,66 @@ pub fn specs() -> Vec<CommandSpec> {
        cmd!("photo.rotateRight", "Rotate Right", ["Photo"], Some("Cmd+]"), "{ids?}", has_selection, |s, p| rotate(s, p, true)),
        cmd!("photo.flipHorizontal", "Flip Horizontal", ["Photo"], None, "{ids?}", has_selection, |s, p| flip(s, p, true)),
        cmd!("photo.flipVertical", "Flip Vertical", ["Photo"], None, "{ids?}", has_selection, |s, p| flip(s, p, false)),
+        // ---- face / pet regions
+        cmd!(
+            "photo.removeRegion",
+            "Remove Face Box",
+            [],
+            None,
+            "{id?, index} — remove one face / pet region (by its position in the photo's regions) from the photo in the catalog; undoable. The XMP sidecar is never rewritten for this, even with auto-write on, so reading the metadata from the file brings the region back",
+            always,
+            |s, p| {
+                let id =
+                    p.get("id").and_then(Value::as_u64).map(PhotoId).or_else(|| s.active()).ok_or_else(|| bad("photo.removeRegion", "no photo"))?;
+                let index = p
+                    .get("index")
+                    .and_then(Value::as_u64)
+                    .and_then(|i| usize::try_from(i).ok())
+                    .ok_or_else(|| bad("photo.removeRegion", "missing or invalid `index`"))?;
+                let mut meta = s.catalog.photo(id).ok_or_else(|| bad("photo.removeRegion", "no such photo"))?.meta.clone();
+                if index >= meta.regions.len() {
+                    return Err(bad("photo.removeRegion", "no such region"));
+                }
+                let gone = meta.regions.remove(index);
+                s.commit("Remove Face Box", Op::SetMeta { id, meta: Box::new(meta) })?;
+                s.skip_auto_write = true;
+                Ok(json!({"removed": gone.name}))
+            }
+        ),
+        cmd!(
+            "photo.setRegion",
+            "Resize Face Box",
+            [],
+            None,
+            "{id?, index, rect: {x0, y0, x1, y1}} — set one face / pet region's box (normalized, in the photo's upright frame; clamped to the photo, at least 0.5 % each way) in the catalog; undoable. Like photo.removeRegion it never rewrites the XMP sidecar",
+            always,
+            |s, p| {
+                const C: &str = "photo.setRegion";
+                // a drag is one undo step however many frames it took: the caller commits once, on release
+                let id = p.get("id").and_then(Value::as_u64).map(PhotoId).or_else(|| s.active()).ok_or_else(|| bad(C, "no photo"))?;
+                let index = p
+                    .get("index")
+                    .and_then(Value::as_u64)
+                    .and_then(|i| usize::try_from(i).ok())
+                    .ok_or_else(|| bad(C, "missing or invalid `index`"))?;
+                let r = p.get("rect").ok_or_else(|| bad(C, "missing `rect`"))?;
+                let num = |k: &str| {
+                    r.get(k).and_then(Value::as_f64).filter(|v| v.is_finite()).ok_or_else(|| bad(C, format!("`rect.{k}` must be a finite number")))
+                };
+                let (a, b, c, d) = (num("x0")?, num("y0")?, num("x1")?, num("y1")?);
+                let (x0, x1) = (a.min(c).clamp(0.0, 1.0), a.max(c).clamp(0.0, 1.0));
+                let (y0, y1) = (b.min(d).clamp(0.0, 1.0), b.max(d).clamp(0.0, 1.0));
+                if x1 - x0 < 0.005 || y1 - y0 < 0.005 {
+                    return Err(bad(C, "the box would be too small"));
+                }
+                let mut meta = s.catalog.photo(id).ok_or_else(|| bad(C, "no such photo"))?.meta.clone();
+                let region = meta.regions.get_mut(index).ok_or_else(|| bad(C, "no such region"))?;
+                region.rect = lightcraft_geom::Rect { x0, y0, x1, y1 };
+                s.commit("Resize Face Box", Op::SetMeta { id, meta: Box::new(meta) })?;
+                s.skip_auto_write = true;
+                Ok(json!({"rect": {"x0": x0, "y0": y0, "x1": x1, "y1": y1}}))
+            }
+        ),
        // ---- delete / restore
        cmd!("photo.delete", "Delete Photo", ["Photo"], Some("Delete"), "{ids?} — moves to Recently Deleted", has_selection, |s, p| {
            let v = for_targets(s, p, "Delete", |id| Some(Op::SetDeleted { id, deleted: true }))?;
@@ -354,14 +658,32 @@ pub fn specs() -> Vec<CommandSpec> {
            s.selection = vis.first().map(|f| Selection::single(*f)).unwrap_or_default();
            Ok(v)
        }),
-        cmd!("photo.restore", "Restore", [], None, "{ids?}", has_selection, |s, p| for_targets(s, p, "Restore", |id| Some(Op::SetDeleted {
+        cmd!("photo.restore", "Restore", ["Photo"], None, "{ids?}", has_selection, |s, p| for_targets(s, p, "Restore", |id| Some(Op::SetDeleted {
            id,
            deleted: false
        }))),
-        cmd!("photo.deletePermanently", "Delete Permanently", [], None, "{ids?}", has_selection, |s, p| {
+        cmd!(
+            "library.emptyRecentlyDeleted",
+            "Empty Recently Deleted",
+            ["Photo"],
+            None,
+            "{} → {deleted} — removes every photo in Recently Deleted from the library (files on disk stay)",
+            always,
+            |s, _| {
+                let ids: Vec<PhotoId> = s.catalog.photos().filter(|p| p.deleted).map(|p| p.id).collect();
+                if ids.is_empty() {
+                    return Ok(json!({"deleted": 0}));
+                }
+                let op = s.catalog.delete_photos_permanently_ops(&ids);
+                s.commit("Empty Recently Deleted", op)?;
+                s.selection = Selection::default();
+                Ok(json!({"deleted": ids.len()}))
+            }
+        ),
+        cmd!("photo.deletePermanently", "Delete Permanently", ["Photo"], None, "{ids?}", has_selection, |s, p| {
            let t = s.targets(p);
-            let ops = t.iter().map(|id| s.catalog.delete_permanently_ops(*id)).collect::<Vec<_>>();
-            s.commit("Delete Permanently", Op::Batch { ops })?;
+            let op = s.catalog.delete_photos_permanently_ops(&t);
+            s.commit("Delete Permanently", op)?;
            s.selection = Selection::default();
            Ok(json!({"deleted": t.len()}))
        }),
@@ -523,8 +845,16 @@ pub fn specs() -> Vec<CommandSpec> {
                let rules = if bool_or(p, "fromView", false) {
                    view_rules(s)
                } else {
-                    let base = if bool_or(p, "replace", false) { Default::default() } else { cur };
-                    merge_rules(&base, p.get("rules").unwrap_or(&Value::Null), "album.setRules")?
+                    let replace = bool_or(p, "replace", false);
+                    let folder = cur.library_folder.clone();
+                    let base = if replace { Default::default() } else { cur };
+                    let mut r = merge_rules(&base, p.get("rules").unwrap_or(&Value::Null), "album.setRules")?;
+                    // the rules dialog has no folder field: replacing its rules keeps the folder
+                    // unless the call says (`libraryFolder: null`) to drop it
+                    if replace && p.get("rules").and_then(|r| r.get("libraryFolder")).is_none() {
+                        r.library_folder = folder;
+                    }
+                    r
                };
                s.commit("Edit Smart Album", Op::SetAlbumRules { id, rules: Box::new(rules) })?;
                Ok(json!({"count": s.catalog.album_count(id)}))
@@ -657,9 +987,9 @@ pub fn specs() -> Vec<CommandSpec> {
            "Auto Import Now",
            [],
            None,
-            "{} — add the watched folder's new photos (files the library doesn't have yet; partial / still-copying files wait for the next scan) → {imported, folder}",
+            "{listing?: [[path, size]] (the folder as listed by the caller, e.g. on a worker thread), start?: bool (false: return the `library.import` params as `import` instead of importing)} — add the watched folder's new photos (files the library doesn't have yet; partial / still-copying files wait for the next scan) → {imported, folder, import?}",
            always,
-            |s, _| {
+            |s, p| {
                let Some(folder) = s.import_defaults.auto_folder.clone() else { return Ok(json!({"imported": [], "folder": null})) };
                // only files that stopped growing: a file still being written is left for later
                let known: std::collections::HashSet<String> = s
@@ -670,18 +1000,20 @@ pub fn specs() -> Vec<CommandSpec> {
                        _ => None,
                    })
                    .collect();
+                // the folder's files and sizes: listed here, or already listed on a worker thread (the app)
+                let listing: Vec<(String, u64)> = match p.get("listing").and_then(Value::as_array) {
+                    Some(l) => l.iter().filter_map(|e| Some((e.get(0)?.as_str()?.to_string(), e.get(1)?.as_u64()?))).collect(),
+                    None => list_auto_import_folder(&folder).map_err(|e| bad("library.autoImportScan", e))?,
+                };
                let mut fresh = Vec::new();
-                for e in std::fs::read_dir(&folder).map_err(|e| bad("library.autoImportScan", format!("{folder}: {e}")))?.flatten() {
-                    let path = e.path();
-                    let ps = path.to_string_lossy().to_string();
-                    if !path.is_file() || known.contains(&ps) || path.file_name().is_some_and(|n| n.to_string_lossy().starts_with('.')) {
+                for (ps, size) in listing {
+                    if known.contains(&ps) {
                        continue;
                    }
                    // each file is tried once (a non-photo isn't retried every scan)
                    if s.auto_import_seen.get(&ps) == Some(&u64::MAX) {
                        continue;
                    }
-                    let size = e.metadata().map(|m| m.len()).unwrap_or(0);
                    let seen = s.auto_import_seen.insert(ps.clone(), size);
                    if size > 0 && seen == Some(size) {
                        fresh.push(ps);
@@ -701,6 +1033,10 @@ pub fn specs() -> Vec<CommandSpec> {
                for f in &fresh {
                    s.auto_import_seen.insert(f.clone(), u64::MAX);
                }
+                if p.get("start").and_then(Value::as_bool) == Some(false) {
+                    // the caller imports them (the app: on a worker thread)
+                    return Ok(json!({"imported": [], "folder": folder, "import": params}));
+                }
                let sel = s.selection.clone();
                let r = s.execute("library.import", &params)?;
                // arriving photos don't take over the selection
@@ -726,6 +1062,25 @@ pub fn specs() -> Vec<CommandSpec> {
            ok()
        }),
        // ---- import
+        cmd!(query "library.inspectLightroom", "Inspect Lightroom Catalog", [], None,
+        "{path: .lrcat} → {photos, collections, missing, warnings}; read-only, no Lightroom required",
+        always, |_, p| {
+            let path = str_param(p,"path").ok_or_else(|| bad("library.inspectLightroom","missing path"))?;
+            let data = crate::lightroom_catalog::read(std::path::Path::new(path)).map_err(|e| bad("library.inspectLightroom",e))?;
+            Ok(json!({"photos":data.photos.len(),"collections":data.collections.iter().filter(|r|r.get("systemOnly").and_then(Value::as_f64).unwrap_or(0.0)==0.0).count(),"missing":data.photos.iter().filter(|p| !std::path::Path::new(&p.path).is_file()).map(|p|&p.path).collect::<Vec<_>>(),"warnings":data.warnings}))
+        }),
+        cmd!(
+            "library.importLightroom",
+            "Import Lightroom Catalog",
+            [],
+            None,
+            "{path: .lrcat, updateExisting?: false}; direct import of paths, ratings, flags, metadata, keywords, collections, virtual copies & mapped edits. Archives source settings/history first. Existing edited photos are preserved unless updateExisting=true; source catalog is read-only.",
+            always,
+            |s, p| {
+                let path = str_param(p, "path").ok_or_else(|| bad("library.importLightroom", "missing path"))?;
+                crate::lightroom_catalog::import(s, std::path::Path::new(path), bool_or(p, "updateExisting", false))
+            }
+        ),
        cmd!(
            query "library.importPreview",
            "Review Import",
@@ -748,84 +1103,23 @@ pub fn specs() -> Vec<CommandSpec> {
            "Import Photos",
            ["File"],
            Some("Cmd+Shift+I"),
-            "{paths: [file or folder (recursive)], mode?: add|copy|move (add = reference the files in place; copy = into the library's Originals/YYYY/YYYY-MM-DD/; move = as copy, then each original and its XMP sidecars are removed from the source — only after the copy is verified (a hard link on the same volume, else copied, synced and compared byte for byte) and its catalog record is saved; failed, duplicate and unchecked files keep their sources; a taken name gets -1, -2…; undo removes the photos from the library but leaves the files at the destination), destination?: folder for copies / moves, organize?: date (YYYY/YYYY-MM-DD) | month (YYYY/YYYY-MM) | flat | a folder template, e.g. `{date:%Y}/{date:%Y%m%d}` → 2026/20260114 (the template's `/` make the folders, each level expanded with the rename tokens and made a safe folder name: never outside the destination; must be relative, no `..`; a level with missing metadata is `unknown`) — dated by capture time, else the import time, rename?: file-name template for copies, original extension added (tokens: {name} {num} {seq} {seq:N} {date} {date:%Y%m%d} {folder} {camera} {lens} {iso} {rating} {title} {creator} {ext}; photo.renameTokens explains each; blank = keep names), renameStart?: 1, metadataPreset?: name, dng?: bool (copy raws as DNG; copy only), local?: bool (browsing: the photos stay out of the library, like library.browse; not with move), album?: albumId, albumName?: new album, preset?: presetId, keywords?: [..]} → {imported, duplicates, failed, moved?: [{from, to, sidecars?}], kept?: [{path, reason}] (move: sources left in place and why), album?}",
+            "{paths: [file or folder (recursive)], mode?: add|copy|move (add = reference the files in place; copy = into the library's Originals/YYYY/YYYY-MM-DD/; move = as copy, then each original and its XMP sidecars are removed from the source — only after the copy is verified (a hard link on the same volume, else copied, synced and compared byte for byte) and its catalog record is saved; failed, duplicate and unchecked files keep their sources; a taken name gets -1, -2…; undo removes the photos from the library but leaves the files at the destination), destination?: folder for copies / moves, organize?: date (YYYY/YYYY-MM-DD) | month (YYYY/YYYY-MM) | flat | a folder template, e.g. `{date:%Y}/{date:%Y%m%d}` → 2026/20260114 (the template's `/` make the folders, each level expanded with the rename tokens and made a safe folder name: never outside the destination; must be relative, no `..`; a level with missing metadata is `unknown`) — dated by capture time, else the import time, rename?: file-name template for copies, original extension added (tokens: {name} {num} {seq} {seq:N} {date} {date:%Y%m%d} {folder} {camera} {lens} {iso} {rating} {title} {creator} {ext}; photo.renameTokens explains each; blank = keep names), renameStart?: 1, metadataPreset?: name, dng?: bool (copy raws as DNG; copy only), local?: bool (browsing: the photos stay out of the library, like library.browse; not with move), album?: albumId, albumName?: new album, preset?: presetId, keywords?: [..], onDeleted?: skip|restore|fresh (a file that is in Recently Deleted: skip = leave it there and say so, restore = bring the photo back with its edits, fresh = delete the trashed record and import the file as new)} → {imported, duplicates: [{path, existing, reason, existingDeleted?}], restored?: [photoId], failed, moved?: [{from, to, sidecars?}], kept?: [{path, reason}] (move: sources left in place and why), album?}",
            always,
            |s, p| {
-                let paths = strs(p, "paths");
-                if paths.is_empty() {
+                let req = import_params(s, p)?;
+                if req.paths.is_empty() {
                    return Err(bad("library.import", "no paths"));
                }
-                let mode = match str_param(p, "mode").unwrap_or("add") {
-                    "add" => crate::import::ImportMode::Add,
-                    "copy" => crate::import::ImportMode::Copy,
-                    "move" => crate::import::ImportMode::Move,
-                    other => return Err(bad("library.import", format!("unknown mode `{other}` (add|copy|move)"))),
-                };
-                let preset = match str_param(p, "preset").filter(|x| !x.is_empty()) {
-                    Some(id) => {
-                        Some(s.presets.iter().find(|x| x.id == id).cloned().ok_or_else(|| bad("library.import", format!("unknown preset `{id}`")))?)
-                    }
-                    None => None,
-                };
-                let mut album = p.get("album").and_then(Value::as_u64);
-                if let Some(a) = album
-                    && s.catalog.album(AlbumId(a)).is_none_or(|al| al.folder || al.is_smart())
-                {
-                    return Err(bad("library.import", "album must be a regular album"));
-                }
-                let organize = match str_param(p, "organize") {
-                    Some(o) => crate::import::Organize::parse(o).ok_or_else(|| {
-                        bad(
-                            "library.import",
-                            format!("unknown organize `{o}` (date|month|flat, or a folder template like {{date:%Y}}/{{date:%Y%m%d}})"),
-                        )
-                    })?,
-                    None => Default::default(),
-                };
-                if let crate::import::Organize::Template(t) = &organize
-                    && let Some(e) = crate::rename::folder_template_error(t)
-                {
-                    return Err(bad("library.import", e));
-                }
-                let metadata_preset = str_param(p, "metadataPreset").map(str::trim).filter(|n| !n.is_empty()).map(str::to_string);
-                if let Some(n) = &metadata_preset
-                    && !s.metadata_presets.iter().any(|m| m.name.eq_ignore_ascii_case(n))
-                {
-                    return Err(bad("library.import", format!("unknown metadata preset `{n}`")));
-                }
-                let opts = crate::import::ImportOptions {
-                    mode,
-                    preset,
-                    keywords: strs(p, "keywords"),
-                    destination: str_param(p, "destination").map(str::to_string),
-                    organize,
-                    rename: str_param(p, "rename").map(str::to_string),
-                    rename_start: p.get("renameStart").and_then(Value::as_u64).unwrap_or(1) as usize,
-                    metadata_preset,
-                    convert_dng: super::bool_or(p, "dng", false),
-                    local: super::bool_or(p, "local", false),
-                };
                let undo0 = s.undo.len();
-                let mut report = serde_json::to_value(crate::import::import_with(s, &paths, &opts)?).unwrap_or_default();
-                let imported: Vec<u64> = report["imported"].as_array().map(|a| a.iter().filter_map(Value::as_u64).collect()).unwrap_or_default();
-                if album.is_none()
-                    && let Some(name) = str_param(p, "albumName").map(str::trim).filter(|n| !n.is_empty())
-                    && !imported.is_empty()
-                {
-                    let r = s.execute("album.create", &json!({"name": name}))?;
-                    album = r["id"].as_u64();
-                }
-                if let Some(a) = album
-                    && !imported.is_empty()
-                {
-                    // (album.addPhotos wants a selection: the new photos are about to be it)
-                    s.selection = Selection::single(PhotoId(imported[0]));
-                    s.execute("album.addPhotos", &json!({"id": a, "ids": imported}))?;
-                    report["album"] = json!(a);
-                }
+                let report = crate::import::import_with(s, &req.paths, &req.opts)?;
+                let report = import_batch_done(s, report, req.album, req.album_name.as_deref())?;
                // one undo step for the whole import
+                let ids_of = |k: &str| -> Vec<u64> { report[k].as_array().map(|a| a.iter().filter_map(Value::as_u64).collect()).unwrap_or_default() };
+                let (imported, restored) = (ids_of("imported"), ids_of("restored"));
                let n = s.undo.len().saturating_sub(undo0);
-                s.merge_undo(n, &format!("Add {} Photo{}", imported.len(), if imported.len() == 1 { "" } else { "s" }));
+                let (verb, count) = if imported.is_empty() && !restored.is_empty() { ("Restore", restored.len()) } else { ("Add", imported.len()) };
+                s.merge_undo(n, &format!("{verb} {count} Photo{}", if count == 1 { "" } else { "s" }));
+                let imported = if imported.is_empty() { restored } else { imported };
                if let Some(f) = imported.first() {
                    s.selection = Selection::single(PhotoId(*f));
                }
@@ -890,6 +1184,7 @@ pub fn specs() -> Vec<CommandSpec> {
        }),
        cmd!("library.clearPreviews", "Clear Preview Cache", ["File"], None, "{}", always, |s, _| {
            s.media.rendered.clear();
+            s.media.clear_sources();
            ok()
        }),
    ]
@@ -906,6 +1201,16 @@ fn merge_rules(base: &lightcraft_catalog::Filter, patch: &Value, c: &str) -> Res
    Ok(f)
 }

+/// Whether `path` lies above a disk: some of its `ids` photos are on a disk (not the startup
+/// disk) that the folder does not lie in. Such a folder (`/Volumes`, `/mnt`…) is not a folder of
+/// one disk but a way to reach several.
+fn covers_other_disks(s: &Session, path: &str, ids: &[PhotoId]) -> bool {
+    ids.iter()
+        .filter_map(|id| s.catalog.photo(*id))
+        .filter_map(|p| lightcraft_catalog::folders::volume_of(p))
+        .any(|v| v != "/" && !lightcraft_catalog::query::folder_within(path, &v))
+}
+
 /// The current view (source + filter) as smart-album rules. Viewing a smart album starts from
 /// its rules with the filter bar's settings on top.
 fn view_rules(s: &Session) -> lightcraft_catalog::Filter {
@@ -932,6 +1237,9 @@ fn view_rules(s: &Session) -> lightcraft_catalog::Filter {
        None => {
            let mut f = s.source.to_filter(&s.filter, &s.catalog);
            f.deleted = false;
+            if s.source == LibrarySource::LibraryFolder {
+                f.library_folder = s.library_folder.clone();
+            }
            f
        }
    }
@@ -41,22 +41,11 @@ fn cube_files(paths: &[String]) -> Vec<(String, String, Option<String>)> {
    for p in paths {
        let path = Path::new(p);
        if path.is_dir() {
-            let mut stack = vec![path.to_path_buf()];
-            while let Some(d) = stack.pop() {
-                let Ok(rd) = std::fs::read_dir(&d) else { continue };
-                for e in rd.flatten() {
-                    let ep = e.path();
-                    if ep.file_name().is_some_and(|n| n.to_string_lossy().starts_with('.')) {
-                        continue;
-                    }
-                    if ep.is_dir() {
-                        stack.push(ep);
-                    } else if ep.extension().is_some_and(|x| x.eq_ignore_ascii_case("cube"))
-                        && let Ok(t) = std::fs::read_to_string(&ep)
-                    {
-                        let group = ep.parent().and_then(|d| d.file_name()).map(|n| n.to_string_lossy().to_string());
-                        out.push((ep.file_stem().map(|n| n.to_string_lossy().to_string()).unwrap_or_default(), t, group));
-                    }
+            let cube = |f: &Path| f.extension().is_some_and(|x| x.eq_ignore_ascii_case("cube"));
+            for ep in crate::walk::files_in(path, None, crate::walk::Limits::default(), cube).files {
+                if let Ok(t) = std::fs::read_to_string(&ep) {
+                    let group = ep.parent().and_then(|d| d.file_name()).map(|n| n.to_string_lossy().to_string());
+                    out.push((ep.file_stem().map(|n| n.to_string_lossy().to_string()).unwrap_or_default(), t, group));
                }
            }
        } else if path.extension().is_some_and(|x| x.eq_ignore_ascii_case("zip")) {
@@ -5,6 +5,7 @@ use lightcraft_geom::Point;
 use serde_json::{Value, json};

 use super::{CommandSpec, bad, bool_or, cmd, f64_or, has_active, ok, point, str_param};
+use crate::segment::{Click, MAX_CLICKS};
 use crate::{Result, Session};

 fn shape_from(kind: &str, p: &Value, c: &str) -> Result<MaskShape> {
@@ -38,10 +39,100 @@ fn shape_from(kind: &str, p: &Value, c: &str) -> Result<MaskShape> {
                .unwrap_or_default();
            MaskShape::ColorRange { samples, refine: f64_or(p, "refine", 50.0) }
        }
-        other => return Err(bad(c, format!("unknown mask kind `{other}` (brush|linear|radial|sky|subject|background|luminanceRange|colorRange)"))),
+        "object" => MaskShape::Object { hint: points(p, "points"), exclude: points(p, "exclude"), seg: seg_param(p), detail: vec![], edge: 0.0 },
+        "prompt" => {
+            MaskShape::Prompt { text: str_param(p, "text").unwrap_or_default().trim().to_string(), seg: seg_param(p), detail: vec![], edge: 0.0 }
+        }
+        other => {
+            return Err(bad(
+                c,
+                format!("unknown mask kind `{other}` (brush|linear|radial|sky|subject|background|luminanceRange|colorRange|object|prompt)"),
+            ));
+        }
    })
 }

+/// `[[x, y], …]` normalized points under `key`.
+fn points(p: &Value, key: &str) -> Vec<Point> {
+    p.get(key)
+        .and_then(Value::as_array)
+        .map(|a| a.iter().filter_map(|q| Some(Point::new(q.get(0)?.as_f64()?, q.get(1)?.as_f64()?))).collect())
+        .unwrap_or_default()
+}
+
+/// A segmentation passed in (`seg`: a stored or replayed AI mask; the model isn't needed).
+fn seg_param(p: &Value) -> Option<lightcraft_develop::SegMask> {
+    p.get("seg").and_then(|v| serde_json::from_value(v.clone()).ok())
+}
+
+/// What a new AI shape still needs once it is added.
+enum Later {
+    Nothing,
+    /// Background mode: these Object clicks are segmented on the worker.
+    Clicks(Vec<Point>, Vec<Point>),
+    /// Background mode: the Describe selection is computed first; the mask is added when found.
+    Text(String),
+}
+
+/// Compute the segmentation of a new AI shape (Object with clicks, Prompt) — or, in background
+/// mode, say what to queue. An Object without clicks stays empty until the photo is clicked
+/// (the photo is analyzed meanwhile); a Prompt that matches nothing is an error. Shapes given
+/// with their `seg` need no model.
+fn resolve_ai(s: &mut Session, shape: &mut MaskShape, c: &str) -> Result<Later> {
+    let id = s.active().ok_or_else(|| bad(c, "no active photo"))?;
+    let background = s.segmenter.background;
+    match shape {
+        MaskShape::Object { seg: Some(_), .. } | MaskShape::Prompt { seg: Some(_), .. } => {}
+        MaskShape::Object { hint, exclude, .. } if !hint.is_empty() && background => {
+            s.segmenter.model_dir().map_err(ai_err)?;
+            return Ok(Later::Clicks(std::mem::take(hint), std::mem::take(exclude)));
+        }
+        MaskShape::Object { hint, exclude, seg, .. } if !hint.is_empty() => {
+            *seg = Some(s.segment_clicks(id, &clicks_of(hint, exclude)).map_err(ai_err)?);
+        }
+        MaskShape::Object { .. } => {
+            // the clicks come later: refuse an Object mask that could never be computed (no
+            // model) rather than leave an empty one; in the app, analyze the photo meanwhile
+            s.segmenter.model_dir().map_err(ai_err)?;
+            if background {
+                s.segment_prepare(id).map_err(ai_err)?;
+            }
+        }
+        MaskShape::Prompt { text, .. } if background => {
+            s.segmenter.model_dir().map_err(ai_err)?;
+            if text.trim().is_empty() {
+                return Err(ai_err("describe what to select"));
+            }
+            return Ok(Later::Text(text.clone()));
+        }
+        MaskShape::Prompt { text, seg, .. } => {
+            let found = s.segment_text(id, text).map_err(ai_err)?;
+            *seg = Some(found.ok_or_else(|| ai_err(format!("nothing matching “{text}” was found in this photo")))?);
+        }
+        _ => {}
+    }
+    Ok(Later::Nothing)
+}
+
+/// Queue what a new AI component (component `comp` of mask `mask`) still needs.
+fn queue_later(s: &mut Session, later: Later, mask: u32, comp: usize, mut out: Value) -> Result<Value> {
+    if let Later::Clicks(hint, exclude) = later {
+        let id = s.active().ok_or_else(|| ai_err("no active photo"))?;
+        s.segment_clicks_later(id, mask, comp, hint, exclude).map_err(ai_err)?;
+        out["pending"] = json!(true);
+    }
+    Ok(out)
+}
+
+/// AI mask failures are shown as they are (not as "invalid parameters").
+fn ai_err(msg: impl Into<String>) -> crate::EngineError {
+    crate::EngineError::Other(msg.into())
+}
+
+pub(crate) fn clicks_of(include: &[Point], exclude: &[Point]) -> Vec<Click> {
+    include.iter().map(|p| Click { at: *p, include: true }).chain(exclude.iter().map(|p| Click { at: *p, include: false })).collect()
+}
+
 fn masks_edit(s: &mut Session, c: &str, label: &str, f: impl FnOnce(&mut Vec<Mask>, &mut Option<u32>) -> Result<()>) -> Result<Value> {
    let id = s.active().ok_or_else(|| bad(c, "no active photo"))?;
    let mut d = (*s.develop_of(id).unwrap_or_default()).clone();
@@ -67,14 +158,20 @@ pub fn specs() -> Vec<CommandSpec> {
            "Create New Mask",
            [],
            None,
-            "{kind: brush|linear|radial|sky|subject|background|luminanceRange|colorRange, ...shape params (start/end, center/rx/ry/angle/feather, lo/hi…), name?}",
+            "{kind: brush|linear|radial|sky|subject|background|luminanceRange|colorRange|object|prompt, ...shape params (start/end, center/rx/ry/angle/feather, lo/hi…; object: points/exclude [[x,y],…]; prompt: text; object/prompt: seg? a stored segmentation, no model needed), name?} — AI kinds need the SAM 3 model; in the app a prompt returns {pending} and the mask appears when found",
            has_active,
            |s, p| {
                let kind = str_param(p, "kind").unwrap_or("radial").to_string();
-                let shape = shape_from(&kind, p, "mask.add")?;
+                let mut shape = shape_from(&kind, p, "mask.add")?;
+                let later = resolve_ai(s, &mut shape, "mask.add")?;
                let name = str_param(p, "name").map(str::to_string);
+                if let Later::Text(text) = &later {
+                    let id = s.active().ok_or_else(|| bad("mask.add", "no active photo"))?;
+                    s.segment_text_later(id, None, "add", name, text).map_err(ai_err)?;
+                    return Ok(json!({"pending": true}));
+                }
                let next = s.active().and_then(|id| s.develop_of(id)).map(|d| d.next_mask_id()).unwrap_or(1);
-                masks_edit(s, "mask.add", "Add Mask", |masks, active| {
+                let out = masks_edit(s, "mask.add", "Add Mask", |masks, active| {
                    masks.push(Mask {
                        id: next,
                        name: name.unwrap_or_else(|| format!("Mask {next}")),
@@ -83,7 +180,8 @@ pub fn specs() -> Vec<CommandSpec> {
                    });
                    *active = Some(next);
                    Ok(())
-                })
+                })?;
+                queue_later(s, later, next, 0, out)
            }
        ),
        cmd!(
@@ -95,16 +193,29 @@ pub fn specs() -> Vec<CommandSpec> {
            has_active,
            |s, p| {
                let kind = str_param(p, "kind").unwrap_or("brush").to_string();
-                let shape = shape_from(&kind, p, "mask.addComponent")?;
                let op: MaskOp =
                    serde_json::from_value(p.get("op").cloned().unwrap_or(json!("add"))).map_err(|e| bad("mask.addComponent", e.to_string()))?;
                let active = s.active_mask;
                let mid = mask_id(p, active, "mask.addComponent")?;
-                masks_edit(s, "mask.addComponent", "Edit Mask", |masks, _| {
+                let id = s.active().ok_or_else(|| bad("mask.addComponent", "no active photo"))?;
+                if !s.develop_of(id).is_some_and(|d| d.masks.iter().any(|m| m.id == mid)) {
+                    return Err(bad("mask.addComponent", format!("no mask {mid}")));
+                }
+                let mut shape = shape_from(&kind, p, "mask.addComponent")?;
+                let later = resolve_ai(s, &mut shape, "mask.addComponent")?;
+                if let Later::Text(text) = &later {
+                    let op = p.get("op").and_then(Value::as_str).unwrap_or("add");
+                    s.segment_text_later(id, Some(mid), op, None, text).map_err(ai_err)?;
+                    return Ok(json!({"pending": true}));
+                }
+                let mut comp = 0;
+                let out = masks_edit(s, "mask.addComponent", "Edit Mask", |masks, _| {
                    let i = find(masks, mid, "mask.addComponent")?;
                    masks[i].components.push(MaskComponent { name: None, op, invert: bool_or(p, "invert", false), shape });
+                    comp = masks[i].components.len() - 1;
                    Ok(())
-                })
+                })?;
+                queue_later(s, later, mid, comp, out)
            }
        ),
        cmd!(
@@ -185,7 +296,7 @@ pub fn specs() -> Vec<CommandSpec> {
                let add = p.get("add").and_then(Value::as_bool).unwrap_or(false);
                let id = s.active().ok_or_else(|| bad(c, "no active photo"))?;
                let src = s.source_now(id, crate::media::SourceLevel::Thumb).map_err(|e| bad(c, e))?;
-                let info = s.catalog.photo(id).map(|p| crate::media::source_info(p)).unwrap_or_default();
+                let info = s.source_info(id);
                let d = s.develop_of(id).unwrap_or_default();
                let req = lightcraft_pipeline::RenderRequest::fit(384, 384);
                let lab = lightcraft_pipeline::color_range_sample(&src, &info, &d, &req, lightcraft_geom::Point::new(x, y))
@@ -213,6 +324,158 @@ pub fn specs() -> Vec<CommandSpec> {
                Ok(json!({"samples": out}))
            }
        ),
+        cmd!(
+            "mask.objectPoint",
+            "Add Object Click",
+            [],
+            None,
+            "{x, y: normalized image point, exclude?: bool (⌥-click: leave this part out), id?: maskId} — a click on the selected mask's Object selection (its last Object component); SAM 3 re-segments the object → {include, exclude}",
+            has_active,
+            |s, p| {
+                let c = "mask.objectPoint";
+                let at = Point::new(super::f64_req(p, "x", c)?, super::f64_req(p, "y", c)?);
+                if !(0.0..=1.0).contains(&at.x) || !(0.0..=1.0).contains(&at.y) {
+                    return Err(bad(c, "the point is outside the photo"));
+                }
+                let exclude = bool_or(p, "exclude", false);
+                let id = s.active().ok_or_else(|| bad(c, "no active photo"))?;
+                let mid = mask_id(p, s.active_mask, c)?;
+                let d = s.develop_of(id).unwrap_or_default();
+                let m = d.masks.iter().find(|m| m.id == mid).ok_or_else(|| bad(c, format!("no mask {mid}")))?;
+                let k = m
+                    .components
+                    .iter()
+                    .rposition(|x| matches!(x.shape, MaskShape::Object { .. }))
+                    .ok_or_else(|| bad(c, "the mask has no Object selection (add one first)"))?;
+                let Some(MaskShape::Object { hint, exclude: ex, edge, .. }) = m.components.get(k).map(|x| &x.shape) else {
+                    return Err(bad(c, "not an Object component"));
+                };
+                let (mut hint, mut ex, edge) = (hint.clone(), ex.clone(), *edge);
+                // clicks still on their way to the model count too
+                if let Some(pending) = s.segmenter.pending_clicks().filter(|q| (q.photo, q.mask, q.comp) == (id, mid, k)) {
+                    (hint, ex) = (pending.hint.clone(), pending.exclude.clone());
+                }
+                if hint.len() + ex.len() >= MAX_CLICKS {
+                    return Err(ai_err(format!("an Object selection takes at most {MAX_CLICKS} clicks; start a new one")));
+                }
+                if exclude {
+                    ex.push(at)
+                } else {
+                    hint.push(at)
+                }
+                if s.segmenter.background && !hint.is_empty() {
+                    let out = json!({"include": hint.len(), "exclude": ex.len(), "pending": true});
+                    s.segment_clicks_later(id, mid, k, hint, ex).map_err(ai_err)?;
+                    return Ok(out);
+                }
+                let seg = if hint.is_empty() { None } else { Some(s.segment_clicks(id, &clicks_of(&hint, &ex)).map_err(ai_err)?) };
+                let out = json!({"include": hint.len(), "exclude": ex.len()});
+                masks_edit(s, c, "Object Mask", |masks, _| {
+                    let i = find(masks, mid, c)?;
+                    if let Some(comp) = masks[i].components.get_mut(k) {
+                        comp.shape = MaskShape::Object { hint, exclude: ex, seg, detail: vec![], edge };
+                    }
+                    Ok(())
+                })?;
+                Ok(out)
+            }
+        ),
+        cmd!(
+            "mask.refineDetail",
+            "Refine AI Mask Detail",
+            [],
+            None,
+            "{id?: maskId, component?} — a zoomed-in SAM 3 pass over an Object/Describe selection (default: the mask's last one): the photo around it is analyzed again at a higher resolution, in the background; the mask updates when it's done → {started}",
+            has_active,
+            |s, p| {
+                let c = "mask.refineDetail";
+                let id = s.active().ok_or_else(|| bad(c, "no active photo"))?;
+                let mid = mask_id(p, s.active_mask, c)?;
+                let d = s.develop_of(id).unwrap_or_default();
+                let m = d.masks.iter().find(|m| m.id == mid).ok_or_else(|| bad(c, format!("no mask {mid}")))?;
+                let k = match p.get("component").and_then(Value::as_u64) {
+                    Some(k) => k as usize,
+                    None => m
+                        .components
+                        .iter()
+                        .rposition(|x| matches!(x.shape, MaskShape::Object { .. } | MaskShape::Prompt { .. }))
+                        .ok_or_else(|| bad(c, "the mask has no Object or Describe selection"))?,
+                };
+                let started = s.segment_detail(id, mid, k).map_err(ai_err)?;
+                Ok(json!({"started": started}))
+            }
+        ),
+        cmd!(
+            query "segment.prepare",
+            "Prepare AI Masks",
+            [],
+            None,
+            "{} — load SAM 3 and analyze the active photo in the background, so Object clicks are instant → {busy}",
+            has_active,
+            |s, _| {
+                let c = "segment.prepare";
+                let id = s.active().ok_or_else(|| bad(c, "no active photo"))?;
+                s.segment_prepare(id).map_err(ai_err)?;
+                Ok(json!({"busy": s.segmenter.busy()}))
+            }
+        ),
+        cmd!(
+            query "segment.model.status",
+            "AI Mask Model Status",
+            [],
+            None,
+            "{} — whether this build has AI masks, whether the SAM 3 model is installed (and where), loaded, busy, and the download's progress → {available, installed, dir, loaded, busy, analyzing, sizeBytes, license, licenseUrl, mirrors, download: {running, done, total, file, error, finished}}",
+            super::always,
+            |s, _| {
+                let g = &s.segmenter;
+                Ok(json!({
+                    "available": crate::segment::Segmenter::AVAILABLE,
+                    "installed": g.installed(),
+                    "dir": g.dir.as_ref().map(|d| d.display().to_string()),
+                    "loaded": g.loaded(),
+                    "busy": g.busy(),
+                    "analyzing": g.analyzing(),
+                    "sizeBytes": crate::segment::MODEL_BYTES,
+                    "license": crate::segment::LICENSE_NAME,
+                    "licenseUrl": crate::segment::LICENSE_URL,
+                    "mirrors": g.mirrors().len(),
+                    "download": g.download_status(),
+                }))
+            }
+        ),
+        cmd!(
+            query "segment.model.download",
+            "Download AI Mask Model",
+            [],
+            None,
+            "{acknowledged: true} — download the SAM 3 model (about 3.4 GB, Meta's SAM License, not LightCraft's) in the background, from the configured mirrors; only after the user agreed to it. Watch segment.model.status; segment.model.cancel stops it (it resumes later) → {started, installed, downloading}",
+            super::always,
+            |s, p| {
+                let c = "segment.model.download";
+                if p.get("acknowledged").and_then(Value::as_bool) != Some(true) {
+                    return Err(bad(
+                        c,
+                        format!(
+                            "the SAM 3 model is a {:.1} GB download under Meta's {} ({}): pass `acknowledged: true` once the user has agreed to download it",
+                            crate::segment::MODEL_BYTES as f64 / 1e9,
+                            crate::segment::LICENSE_NAME,
+                            crate::segment::LICENSE_URL
+                        ),
+                    ));
+                }
+                let started = s.segmenter.start_download().map_err(ai_err)?;
+                Ok(json!({"started": started, "installed": s.segmenter.installed(), "downloading": s.segmenter.download_status().running}))
+            }
+        ),
+        cmd!(
+            query "segment.model.cancel",
+            "Cancel AI Mask Model Download",
+            [],
+            None,
+            "{} — stop the SAM 3 download (what has arrived is kept, and a new download resumes from it) → {cancelled}",
+            super::always,
+            |s, _| Ok(json!({"cancelled": s.segmenter.cancel_download()}))
+        ),
        cmd!(
            "mask.refine",
            "Refine Mask Edges",
@@ -646,7 +909,7 @@ fn spots_edit(s: &mut Session, c: &str, label: &str, f: impl FnOnce(&mut Vec<Spo
 /// An automatic source for `spot` on photo `id` (a small proxy of the photo, framed by `d`).
 fn pick_source(s: &mut Session, id: crate::PhotoId, d: &lightcraft_develop::DevelopSettings, spot: &Spot, avoid: Option<Point>) -> Option<Point> {
    let src = s.source_now(id, crate::media::SourceLevel::Thumb).ok()?;
-    let info = crate::media::source_info(s.catalog.photo(id)?);
+    let info = s.source_info(id);
    lightcraft_pipeline::spots::pick_source(&src, &info, d, spot, avoid)
 }

@@ -45,9 +45,10 @@ pub fn missing(s: &Session) -> Vec<(PhotoId, String)> {
 }

 /// Whether photo `id` is in scope and its file is gone (the Missing Photos view checks only
-/// the photos its query already narrowed to).
-pub fn is_missing(cat: &Catalog, id: PhotoId) -> bool {
-    !cfg!(target_arch = "wasm32") && cat.photo(id).and_then(|p| checked_path(p)).is_some_and(|f| !Path::new(f).exists())
+/// the photos its query already narrowed to). In the app `avail` answers from its cache (files
+/// not checked yet count as present until the background check finds them gone).
+pub fn is_missing(cat: &Catalog, avail: &crate::availability::Availability, id: PhotoId) -> bool {
+    !cfg!(target_arch = "wasm32") && cat.photo(id).and_then(|p| checked_path(p)).is_some_and(|f| avail.is_offline(f))
 }

 fn relink_op(id: PhotoId, path: &str) -> Op {
@@ -94,8 +95,112 @@ fn file_hash(path: &str) -> Option<String> {
    std::fs::read(path).ok().map(|b| lightcraft_preview::hash_bytes(&b).to_string())
 }

-/// Search `folder` (recursively) for each missing photo's file and relink every match in one
-/// undoable step.
+/// An in-scope photo ([`checked_path`]) as Find Missing Photos sees it: its file, the size and
+/// content hash the library knows (0 / `None` = unknown).
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct FindCandidate {
+    pub id: PhotoId,
+    pub path: String,
+    pub size: u64,
+    pub hash: Option<String>,
+}
+
+/// Every in-scope photo, for [`plan_find_missing`]: the missing ones are looked for, and no
+/// photo's file is used for another. No file-system calls, so the app takes this snapshot on the
+/// UI thread and plans on a worker without holding the session.
+pub fn find_candidates(cat: &Catalog) -> Vec<FindCandidate> {
+    cat.photos()
+        .filter_map(|p| {
+            checked_path(p).map(|f| FindCandidate { id: p.id, path: f.to_string(), size: p.file_size, hash: stored_hash(p).map(str::to_string) })
+        })
+        .collect()
+}
+
+/// How a missing photo's file was recognised.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum MatchBy {
+    /// Same name and size (and content, when the library knows its hash).
+    Name,
+    /// Renamed: same size and content hash.
+    Content,
+}
+
+impl MatchBy {
+    pub fn as_str(self) -> &'static str {
+        match self {
+            MatchBy::Name => "name",
+            MatchBy::Content => "content",
+        }
+    }
+}
+
+/// A missing photo and the file found for it.
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct FoundFile {
+    pub id: PhotoId,
+    pub from: String,
+    pub to: String,
+    pub by: MatchBy,
+}
+
+/// A missing photo with several look-alike files (same name and size, no hash to tell them
+/// apart): skipped, never guessed.
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct AmbiguousFile {
+    pub id: PhotoId,
+    pub from: String,
+    pub candidates: Vec<String>,
+}
+
+/// What Find Missing Photos found ([`plan_find_missing`]), before relinking.
+#[derive(Clone, Debug, Default, PartialEq, Eq)]
+pub struct FindPlan {
+    pub found: Vec<FoundFile>,
+    /// In-scope photos that stay missing (the ambiguous ones included).
+    pub missing: usize,
+    pub ambiguous: Vec<AmbiguousFile>,
+}
+
+impl FindPlan {
+    /// `{found: [{id, from, to, by}], missing, ambiguous: [{id, from, candidates}]}` — the
+    /// command's result, and what `library.findMissing {found, …}` takes back.
+    pub fn to_json(&self) -> Value {
+        let found: Vec<Value> = self.found.iter().map(|f| json!({"id": f.id.0, "from": f.from, "to": f.to, "by": f.by.as_str()})).collect();
+        let ambiguous: Vec<Value> = self.ambiguous.iter().map(|a| json!({"id": a.id.0, "from": a.from, "candidates": a.candidates})).collect();
+        json!({"found": found, "missing": self.missing, "ambiguous": ambiguous})
+    }
+
+    /// The inverse of [`FindPlan::to_json`] (entries it can't read are dropped).
+    pub fn from_json(v: &Value) -> FindPlan {
+        let list = |k: &str| v.get(k).and_then(Value::as_array).cloned().unwrap_or_default();
+        let found = list("found")
+            .iter()
+            .filter_map(|f| {
+                let by = if f.get("by").and_then(Value::as_str) == Some("content") { MatchBy::Content } else { MatchBy::Name };
+                Some(FoundFile {
+                    id: PhotoId(f.get("id")?.as_u64()?),
+                    from: str_param(f, "from")?.to_string(),
+                    to: str_param(f, "to")?.to_string(),
+                    by,
+                })
+            })
+            .collect();
+        let ambiguous = list("ambiguous")
+            .iter()
+            .filter_map(|a| {
+                let candidates = a.get("candidates")?.as_array()?.iter().filter_map(|c| c.as_str().map(str::to_string)).collect();
+                Some(AmbiguousFile { id: PhotoId(a.get("id")?.as_u64()?), from: str_param(a, "from")?.to_string(), candidates })
+            })
+            .collect();
+        let missing = v.get("missing").and_then(Value::as_u64).map_or(0, |n| usize::try_from(n).unwrap_or(usize::MAX));
+        FindPlan { found, missing, ambiguous }
+    }
+}
+
+/// The file-system half of Find Missing Photos: which `candidates` are gone, and which file in
+/// `folder` (recursively) is each one's. Touches only the disk — never the session — so the app
+/// runs it on a worker thread (walking a big folder on a network share and hashing look-alikes
+/// takes a while) and relinks the result with `library.findMissing {found, missing, ambiguous}`.
 ///
 /// Matching, per photo:
 /// 1. a file with the same name (any letter case), the same size and the same content hash;
@@ -107,20 +212,21 @@ fn file_hash(path: &str) -> Option<String> {
 ///
 /// Files that are already some photo's original, or that another photo was just matched with,
 /// are not used.
-fn find_missing(s: &mut Session, p: &Value) -> Result<Value> {
-    const C: &str = "library.findMissing";
-    let folder = str_param(p, "folder").ok_or_else(|| bad(C, "missing `folder`"))?;
+pub fn plan_find_missing(candidates: &[FindCandidate], folder: &str) -> std::result::Result<FindPlan, String> {
    if !Path::new(folder).is_dir() {
-        return Err(bad(C, format!("{folder}: not a folder")));
+        return Err(format!("{folder}: not a folder"));
    }
-    let lost = missing(s);
+    if cfg!(target_arch = "wasm32") {
+        return Ok(FindPlan::default());
+    }
+    let lost: Vec<&FindCandidate> = candidates.iter().filter(|c| !Path::new(&c.path).exists()).collect();
    if lost.is_empty() {
-        return Ok(json!({"found": [], "missing": 0, "ambiguous": []}));
+        return Ok(FindPlan::default());
    }
-    let in_use: HashSet<String> = s.catalog.photos().filter_map(|p| checked_path(p).map(str::to_string)).collect();
+    let in_use: HashSet<&str> = candidates.iter().map(|c| c.path.as_str()).collect();
    // file name (lower case) → candidate paths; size → paths (filled lazily)
    let mut by_name: HashMap<String, Vec<String>> = HashMap::new();
-    let files: Vec<String> = crate::import::expand(&[folder.to_string()], None).into_iter().filter(|f| !in_use.contains(f)).collect();
+    let files: Vec<String> = crate::import::expand(&[folder.to_string()], None).into_iter().filter(|f| !in_use.contains(f.as_str())).collect();
    for f in &files {
        if let Some(n) = Path::new(f).file_name() {
            by_name.entry(n.to_string_lossy().to_lowercase()).or_default().push(f.clone());
@@ -131,24 +237,21 @@ fn find_missing(s: &mut Session, p: &Value) -> Result<Value> {
    let mut hash_of = |f: &str| hashes.entry(f.to_string()).or_insert_with(|| file_hash(f)).clone();
    let size_of = |f: &str| std::fs::metadata(f).map(|m| m.len()).ok();
    let mut used: HashSet<String> = HashSet::new();
-    let mut ops = Vec::new();
-    let mut found = Vec::new();
-    let mut ambiguous = Vec::new();
-    for (id, old) in &lost {
-        let Some(ph) = s.catalog.photo(*id) else { continue };
-        let name = Path::new(old).file_name().map(|n| n.to_string_lossy().to_lowercase()).unwrap_or_default();
-        let size = ph.file_size;
-        let hash = stored_hash(ph).map(str::to_string);
+    let mut plan = FindPlan::default();
+    for c in &lost {
+        let name = Path::new(&c.path).file_name().map(|n| n.to_string_lossy().to_lowercase()).unwrap_or_default();
+        let size = c.size;
+        let hash = c.hash.as_deref();
        let named: Vec<&String> = by_name
            .get(&name)
-            .map(|c| c.iter().filter(|f| !used.contains(*f) && (size == 0 || size_of(f) == Some(size))).collect())
+            .map(|v| v.iter().filter(|f| !used.contains(*f) && (size == 0 || size_of(f) == Some(size))).collect())
            .unwrap_or_default();
        // 1. same name and size, confirmed by the content hash
-        let mut hit: Option<(String, &str)> =
-            hash.as_deref().and_then(|h| named.iter().find(|f| hash_of(f).as_deref() == Some(h))).map(|f| (f.to_string(), "name"));
+        let mut hit: Option<(String, MatchBy)> =
+            hash.and_then(|h| named.iter().find(|f| hash_of(f).as_deref() == Some(h))).map(|f| (f.to_string(), MatchBy::Name));
        // 2. renamed: same size and content
        if hit.is_none()
-            && let Some(h) = &hash
+            && let Some(h) = hash
            && size > 0
        {
            let sizes = by_size.get_or_insert_with(|| {
@@ -162,36 +265,75 @@ fn find_missing(s: &mut Session, p: &Value) -> Result<Value> {
            });
            hit = sizes
                .get(&size)
-                .and_then(|c| c.iter().find(|f| !used.contains(*f) && hash_of(f).as_deref() == Some(h.as_str())))
-                .map(|f| (f.clone(), "content"));
+                .and_then(|v| v.iter().find(|f| !used.contains(*f) && hash_of(f).as_deref() == Some(h)))
+                .map(|f| (f.clone(), MatchBy::Content));
        }
        // 3. same name and size only (no hash, or the file was edited in place): one candidate
        //    is taken, several are ambiguous and skipped rather than guessed
        if hit.is_none() {
-            match named.len() {
-                1 => hit = Some((named[0].clone(), "name")),
-                0 => {}
+            match named.as_slice() {
+                [one] => hit = Some(((*one).clone(), MatchBy::Name)),
+                [] => {}
                _ => {
-                    ambiguous.push(json!({"id": id.0, "from": old, "candidates": named}));
+                    plan.ambiguous.push(AmbiguousFile { id: c.id, from: c.path.clone(), candidates: named.iter().map(|f| (*f).clone()).collect() });
                    continue;
                }
            }
        }
        let Some((path, by)) = hit else { continue };
-        ops.push(relink_op(*id, &path));
-        found.push(json!({"id": id.0, "from": old, "to": path, "by": by}));
-        used.insert(path);
+        used.insert(path.clone());
+        plan.found.push(FoundFile { id: c.id, from: c.path.clone(), to: path, by });
    }
-    let still = lost.len() - found.len();
-    if !ops.is_empty() {
-        s.commit("Find Missing Photos", Op::Batch { ops })?;
+    plan.missing = lost.len() - plan.found.len();
+    Ok(plan)
+}
+
+/// Relink what [`plan_find_missing`] found, in one undoable step, re-checked against the
+/// catalog as it is now (the search may have run on a worker while the library changed): a
+/// photo that no longer points at the path it was missing from (relinked, removed) is left
+/// alone, and a file that is now some photo's original — or that the plan names twice — is not
+/// used (that photo stays missing). `missing` is the plan's count, corrected for what changed
+/// among the photos the plan names.
+fn commit_find(s: &mut Session, plan: FindPlan) -> Result<Value> {
+    let still_at = |cat: &Catalog, id: PhotoId, from: &str| cat.photo(id).and_then(|p| checked_path(p)) == Some(from);
+    let mut in_use: HashSet<String> = candidates(&s.catalog).into_iter().collect();
+    let mut found = Vec::new();
+    let mut missing = plan.missing;
+    for f in plan.found {
+        if !still_at(&s.catalog, f.id, &f.from) {
+            continue;
+        }
+        if in_use.contains(&f.to) {
+            missing += 1;
+            continue;
+        }
+        in_use.insert(f.to.clone());
+        found.push(f);
+    }
+    let planned = plan.ambiguous.len();
+    let ambiguous: Vec<AmbiguousFile> = plan.ambiguous.into_iter().filter(|a| still_at(&s.catalog, a.id, &a.from)).collect();
+    // ambiguous photos relinked meanwhile aren't missing any more
+    missing = missing.saturating_sub(planned - ambiguous.len());
+    if !found.is_empty() {
+        s.commit("Find Missing Photos", Op::Batch { ops: found.iter().map(|f| relink_op(f.id, &f.to)).collect() })?;
        for f in &found {
-            if let Some(id) = f["id"].as_u64() {
-                s.media.forget(PhotoId(id));
-            }
+            s.media.forget(f.id);
        }
    }
-    Ok(json!({"found": found, "missing": still, "ambiguous": ambiguous}))
+    Ok(FindPlan { found, missing, ambiguous }.to_json())
+}
+
+/// Search `folder` (recursively) for each missing photo's file ([`plan_find_missing`]) and
+/// relink every match in one undoable step. With `found` instead (what a search on a worker
+/// thread returned, as `{found, missing, ambiguous}`), only the relinking is done.
+fn find_missing(s: &mut Session, p: &Value) -> Result<Value> {
+    const C: &str = "library.findMissing";
+    if p.get("found").is_some_and(Value::is_array) {
+        return commit_find(s, FindPlan::from_json(p));
+    }
+    let folder = str_param(p, "folder").ok_or_else(|| bad(C, "missing `folder`"))?;
+    let plan = plan_find_missing(&find_candidates(&s.catalog), folder).map_err(|e| bad(C, e))?;
+    commit_find(s, plan)
 }

 pub fn specs() -> Vec<CommandSpec> {
@@ -213,7 +355,7 @@ pub fn specs() -> Vec<CommandSpec> {
            "Find Missing Photos",
            [],
            None,
-            "{folder} — relink every missing photo whose file is somewhere in the folder: same name and size (and content, when the library knows its hash), or — renamed — same size and content → {found: [{id, from, to, by: name|content}], missing, ambiguous: [{id, from, candidates}] (several same-name candidates and no hash to tell them apart: skipped)}",
+            "{folder} — relink every missing photo whose file is somewhere in the folder: same name and size (and content, when the library knows its hash), or — renamed — same size and content; or {found, missing, ambiguous} — relink what a search already found (the app searches on a worker thread; photos relinked meanwhile and files now in use are skipped) → {found: [{id, from, to, by: name|content}], missing, ambiguous: [{id, from, candidates}] (several same-name candidates and no hash to tell them apart: skipped)}",
            always,
            find_missing
        ),
@@ -15,7 +15,7 @@ mod edit;
 mod export;
 pub mod filters;
 pub mod keywords;
-mod library;
+pub mod library;
 pub mod lut_profiles;
 pub mod manage;
 mod masks;
@@ -23,6 +23,12 @@ pub struct PreviewBuild {
    pub failed: AtomicUsize,
    pub cancel: AtomicBool,
    pub finished: AtomicBool,
+    /// Damaged smart previews rebuilt (Build Smart Previews only).
+    pub repaired: AtomicUsize,
+    /// What is built ("" = previews; "smart previews" — Build Smart Previews runs the same way).
+    pub what: &'static str,
+    /// Why the whole build failed (e.g. the smart previews folder isn't there).
+    pub error: std::sync::Mutex<Option<String>>,
 }

 impl PreviewBuild {
@@ -33,8 +39,15 @@ impl PreviewBuild {
            "failed": self.failed.load(Ordering::Relaxed),
            "running": !self.finished.load(Ordering::Relaxed),
            "cancelled": self.cancel.load(Ordering::Relaxed),
+            "what": if self.what.is_empty() { "previews" } else { self.what },
+            "repaired": self.repaired.load(Ordering::Relaxed),
+            "error": self.error(),
        })
    }
+
+    pub fn error(&self) -> Option<String> {
+        self.error.lock().unwrap_or_else(std::sync::PoisonError::into_inner).clone()
+    }
 }

 /// The jobs that build `id`'s previews: the largest grid thumbnail, then the view render at
@@ -94,56 +107,136 @@ fn build(s: &mut Session, p: &Value) -> Result<Value> {
    Ok(state.json())
 }

+/// One photo's smart preview to build or discard: (photo, its file in the smart previews folder,
+/// how to load the original at preview size).
+#[cfg(not(target_arch = "wasm32"))]
+type SmartJob = (lightcraft_catalog::PhotoId, std::path::PathBuf, Option<crate::media::SourceRef>);
+
+/// What Build / Discard Smart Previews did.
+#[cfg(not(target_arch = "wasm32"))]
+#[derive(Default)]
+struct SmartCounts {
+    /// Proxies there now (complete ones kept, missing or damaged ones written).
+    built: usize,
+    /// Of those, damaged ones (cut short by a crash or a full drive) that were rebuilt.
+    repaired: usize,
+    removed: usize,
+    /// `[[id, why]]`
+    failed: Vec<Value>,
+}
+
+/// The file-system half of Build / Discard Smart Previews (runs on a worker thread in the app).
+/// `custom`: the folder was chosen (on another drive, perhaps): it must be there, it is never
+/// recreated. With `state`, progress and cancel.
+#[cfg(not(target_arch = "wasm32"))]
+fn smart_run(
+    dir: &std::path::Path,
+    custom: bool,
+    discard: bool,
+    jobs: Vec<SmartJob>,
+    state: Option<&PreviewBuild>,
+) -> std::result::Result<SmartCounts, String> {
+    let mut n = SmartCounts::default();
+    if !discard {
+        // a chosen folder on another drive must be there: never recreate it on this one
+        if custom {
+            crate::smart::check_writable(dir)?;
+        } else {
+            std::fs::create_dir_all(dir).map_err(|e| format!("{}: {e}", dir.display()))?;
+        }
+    }
+    for (id, path, source) in jobs {
+        if state.is_some_and(|st| st.cancel.load(Ordering::Relaxed)) {
+            break;
+        }
+        if discard {
+            if std::fs::remove_file(&path).is_ok() {
+                n.removed += 1;
+            }
+        } else {
+            // a complete proxy is kept; a missing or damaged one (cut short by a crash or a full
+            // drive) is (re)built
+            let damaged = path.exists();
+            if damaged && crate::smart::is_valid(&path) {
+                n.built += 1;
+            } else {
+                // atomic: a failed write leaves no partial proxy that would pass for a built one;
+                // and synced (issue #134): built so the photo can be edited while its original
+                // is offline, when it is the only copy — the sync is small next to the decode
+                let r = source
+                    .ok_or_else(|| "nothing to build from".to_string())
+                    .and_then(|s| s.load_source())
+                    .and_then(|src| crate::smart::encode(&src.image, src.info_or(Default::default()).camera_tone.as_ref()))
+                    .and_then(|b| lightcraft_catalog::safe_file::write_atomic(&path, &b).map_err(|e| format!("{}: {e}", path.display())));
+                match r {
+                    Ok(()) => {
+                        n.built += 1;
+                        if damaged {
+                            n.repaired += 1;
+                            if let Some(st) = state {
+                                st.repaired.fetch_add(1, Ordering::Relaxed);
+                            }
+                        }
+                    }
+                    Err(e) => {
+                        n.failed.push(json!([id.0, e]));
+                        if let Some(st) = state {
+                            st.failed.fetch_add(1, Ordering::Relaxed);
+                        }
+                    }
+                }
+            }
+        }
+        if let Some(st) = state {
+            st.done.fetch_add(1, Ordering::Relaxed);
+        }
+    }
+    Ok(n)
+}
+
 /// Smart previews: build (from the original, at preview size) or discard the proxies that keep
-/// photos editable while their originals are offline.
+/// photos editable while their originals are offline. With `background` (the app) the files are
+/// read and written on a worker thread; progress like Build Previews (`library.previewProgress`).
 #[cfg(not(target_arch = "wasm32"))]
 fn smart(s: &mut Session, p: &Value) -> Result<Value> {
    const C: &str = "library.smartPreviews";
    let dir = s.media.smart_dir.clone().ok_or_else(|| bad(C, "smart previews need a library on disk"))?;
    let discard = p.get("discard").and_then(Value::as_bool).unwrap_or(false);
-    let ids = if p.get("ids").is_some() || !s.selection.ids.is_empty() { s.targets(p) } else { s.visible_cloned() };
-    let (mut built, mut repaired, mut removed, mut failed) = (0usize, 0usize, 0usize, Vec::new());
-    if !discard {
-        // a chosen folder on another drive must be there: never recreate it on this one
-        if s.smart_previews_dir.is_some() {
-            crate::smart::check_writable(&dir).map_err(|e| bad(C, e))?;
-        } else {
-            std::fs::create_dir_all(&dir).map_err(|e| bad(C, format!("{}: {e}", dir.display())))?;
-        }
+    let background = p.get("background").and_then(Value::as_bool).unwrap_or(false);
+    if background && s.preview_build.as_ref().is_some_and(|b| !b.finished.load(Ordering::Relaxed)) {
+        return Err(bad(C, "a preview build is already running"));
    }
+    let ids = if p.get("ids").is_some() || !s.selection.ids.is_empty() { s.targets(p) } else { s.visible_cloned() };
+    let mut jobs: Vec<SmartJob> = Vec::new();
    for id in ids {
        let Some(ph) = s.catalog.photo(id).cloned() else { continue };
        if !matches!(ph.source, lightcraft_catalog::Source::File { .. }) {
            continue;
        }
        let path = dir.join(crate::smart::file_name(&ph));
-        if discard {
-            if std::fs::remove_file(&path).is_ok() {
-                removed += 1;
-            }
-            continue;
-        }
-        // a complete proxy is kept; a missing or damaged one (cut short by a crash or a full
-        // drive) is (re)built
-        let damaged = path.exists();
-        if damaged && crate::smart::is_valid(&path) {
-            built += 1;
-            continue;
-        }
-        // atomic: a failed write leaves no partial proxy that would pass for a built one
-        let r = s
-            .source_now(id, crate::media::SourceLevel::Preview)
-            .and_then(|src| crate::smart::encode(&src))
-            .and_then(|b| lightcraft_catalog::safe_file::write_atomic(&path, &b).map_err(|e| format!("{}: {e}", path.display())));
-        match r {
-            Ok(()) => {
-                built += 1;
-                repaired += usize::from(damaged);
-            }
-            Err(e) => failed.push(json!([id.0, e])),
-        }
+        let source = (!discard).then(|| s.media.source_ref(&ph, crate::media::SourceLevel::Preview));
+        jobs.push((id, path, source));
    }
-    Ok(json!({"built": built, "repaired": repaired, "removed": removed, "failed": failed}))
+    let custom = s.smart_previews_dir.is_some();
+    if background {
+        let what = if discard { "discarding smart previews" } else { "smart previews" };
+        let state = Arc::new(PreviewBuild { total: jobs.len(), what, ..Default::default() });
+        s.preview_build = Some(state.clone());
+        let st = state.clone();
+        std::thread::Builder::new()
+            .name("lc-smart-previews".into())
+            .spawn(move || {
+                if let Err(e) = smart_run(&dir, custom, discard, jobs, Some(&st)) {
+                    log::warn!("{C}: {e}");
+                    *st.error.lock().unwrap_or_else(std::sync::PoisonError::into_inner) = Some(e);
+                }
+                st.finished.store(true, Ordering::Relaxed);
+            })
+            .map_err(|e| bad(C, format!("could not start: {e}")))?;
+        return Ok(state.json());
+    }
+    let r = smart_run(&dir, custom, discard, jobs, None).map_err(|e| bad(C, e))?;
+    Ok(json!({"built": r.built, "repaired": r.repaired, "removed": r.removed, "failed": r.failed}))
 }

 /// The smart previews folder: where it is, whether it is custom, what it holds, whether it can be
@@ -225,7 +318,7 @@ pub fn specs() -> Vec<CommandSpec> {
            "Build Smart Previews",
            [],
            None,
-            "{ids?, discard?: bool} — build (or discard) the smart previews of the selected photos (else all in view): compact proxies in the library that keep photos editable and exportable (at proxy size) while their originals are offline; a damaged proxy (cut short) is rebuilt → {built, repaired, removed, failed}",
+            "{ids?, discard?: bool, background?: bool} — build (or discard) the smart previews of the selected photos (else all in view): compact proxies in the library that keep photos editable and exportable (at proxy size) while their originals are offline; a damaged proxy (cut short) is rebuilt → {built, repaired, removed, failed}; with background (the app's menu) the files are read and written on a worker thread → {total, done, failed, repaired, running, what} like library.buildPreviews (progress: library.previewProgress, stop: library.cancelPreviews)",
            always,
            smart
        ),
@@ -256,7 +349,7 @@ pub fn specs() -> Vec<CommandSpec> {
            always,
            build
        ),
-        cmd!(query "library.previewProgress", "Preview Build Progress", [], None, "{} → {total, done, failed, running, cancelled} | null", always, |s, _| {
+        cmd!(query "library.previewProgress", "Preview Build Progress", [], None, "{} → {total, done, failed, repaired, running, cancelled, what, error} | null", always, |s, _| {
            Ok(s.preview_build.as_ref().map_or(Value::Null, |b| b.json()))
        }),
        cmd!("library.cancelPreviews", "Cancel Preview Build", [], None, "{}", always, |s, _| {
@@ -5,7 +5,7 @@ use lightcraft_develop::{CONTROLS, controls};
 use serde_json::{Value, json};

 use super::{CommandSpec, always, bad, cmd, has_active};
-use crate::Session;
+use crate::{LibrarySource, Session};

 pub fn photo_summary(p: &Photo) -> Value {
    json!({
@@ -48,8 +48,13 @@ fn album_json(a: &Album, all: &[Album], cat: &lightcraft_catalog::Catalog) -> Va
    v
 }

+/// The photo a query is about: `id` when given (which must be in the library), else the active one.
 fn photo_arg(s: &Session, p: &Value, c: &str) -> crate::Result<PhotoId> {
-    p.get("id").and_then(Value::as_u64).map(PhotoId).or(s.active()).ok_or_else(|| bad(c, "no photo"))
+    match p.get("id").and_then(Value::as_u64).map(PhotoId) {
+        Some(id) if s.catalog.photo(id).is_some() => Ok(id),
+        Some(id) => Err(bad(c, format!("no such photo {}", id.0))),
+        None => s.active().ok_or_else(|| bad(c, "no photo")),
+    }
 }

 pub fn specs() -> Vec<CommandSpec> {
@@ -81,10 +86,14 @@ pub fn specs() -> Vec<CommandSpec> {
            }))
        }),
        cmd!(query "library.state", "Library State", [], None, "{}", always, |s, _| {
-            let label = s.source.label(&s.catalog);
+            let label = match (s.source, s.library_folder.as_deref()) {
+                (LibrarySource::LibraryFolder, Some(path)) => lightcraft_catalog::folders::folder_label(path),
+                _ => s.source.label(&s.catalog),
+            };
            let n = s.visible().len();
            Ok(json!({
                "source": s.source,
+                "libraryFolder": s.library_folder.as_ref().filter(|_| s.source == LibrarySource::LibraryFolder),
                "sourceLabel": label,
                "filter": s.filter,
                "sort": s.sort,
@@ -191,7 +191,7 @@ pub fn devices_in(parents: &[std::path::PathBuf], extra: Vec<std::path::PathBuf>

 /// The volume's `DCIM` folder: the usual spellings are checked directly, so a volume's root is
 /// only listed (other spellings on a case-sensitive volume) off Windows, whose drives aren't.
-fn dcim_in(root: &std::path::Path) -> Option<std::path::PathBuf> {
+pub fn dcim_in(root: &std::path::Path) -> Option<std::path::PathBuf> {
    if let Some(p) = ["DCIM", "dcim"].iter().map(|n| root.join(n)).find(|p| p.is_dir()) {
        return Some(p);
    }
@@ -244,14 +244,53 @@ impl Default for Watermark {

 /// Inter SemiBold (OFL, see assets/ATTRIBUTION.md).
 static WATERMARK_FONT: &[u8] = include_bytes!("../../../assets/fonts/Inter-SemiBold.ttf");
-/// BIZ UDMincho (OFL), Japanese fallback on both native and web.
-/// Bundled OFL Japanese font bytes, shared by watermarks and UI glyph fallback.
-pub static WATERMARK_JAPANESE_FONT: &[u8] = include_bytes!("../../../assets/fonts/BIZUDMincho-Regular.ttf");
+
+/// The watermark faces: Inter first, then the craft-fonts CJK faces (Mincho first, the watermark's
+/// serif look; then any other CJK face — a watermark has no UI language, so every CJK script is
+/// offered). Without craft-fonts that is Inter alone, and CJK characters draw as Inter's
+/// missing-glyph box.
+fn watermark_fonts(craft: &'static [crate::fonts::CraftFont]) -> Vec<ab_glyph::FontRef<'static>> {
+    let mut cjk: Vec<_> = crate::fonts::cjk(craft).collect();
+    cjk.sort_by_key(|f| !f.is_mincho());
+    std::iter::once(WATERMARK_FONT)
+        .chain(cjk.into_iter().map(|f| f.bytes))
+        .filter_map(|bytes| ab_glyph::FontRef::try_from_slice(bytes).ok())
+        .collect()
+}
+
+/// The font's vertical form, positioned from its vertical origin within the watermark cell.
+/// Unlike Unicode presentation-form characters, GSUB works with BIZ UD fonts too.
+fn vertical_watermark_glyph(
+    font: &ab_glyph::FontRef<'_>,
+    data: &harfrust::ShaperData,
+    ch: char,
+    px: f32,
+    left: f32,
+    top: f32,
+) -> Option<ab_glyph::Glyph> {
+    use ab_glyph::{Font, ScaleFont};
+    let face = harfrust::FontRef::new(font.font_data()).ok()?;
+    let mut buf = harfrust::UnicodeBuffer::new();
+    buf.add(ch, 0);
+    buf.set_direction(harfrust::Direction::TopToBottom);
+    buf.guess_segment_properties();
+    let shaped = data.shaper(&face).build().shape(buf, harfrust::ShapeOptions::new());
+    if shaped.glyph_infos().len() != 1 {
+        return None;
+    }
+    let gid = u16::try_from(shaped.glyph_infos().first()?.glyph_id).ok().filter(|g| *g != 0)?;
+    let pos = shaped.glyph_positions().first()?;
+    let sf = font.as_scaled(px);
+    let (sx, sy) = (sf.h_scale_factor(), sf.v_scale_factor());
+    let height = -(pos.y_advance as f32) * sy;
+    let pen = ab_glyph::point(left + px / 2.0 + pos.x_offset as f32 * sx, top + (px - height) / 2.0 - pos.y_offset as f32 * sy);
+    Some(ab_glyph::GlyphId(gid).with_scale_and_position(px, pen))
+}

 /// Draw `wm` onto `img` (straight alpha blending of the encoded values).
 pub fn draw_watermark(img: &mut Rgba8, wm: &Watermark) {
    let width = img.width;
-    watermark_coverage(img.width, img.height, wm, |x, y, k, col| {
+    watermark_coverage(img.width, img.height, wm, crate::fonts::CRAFT_FONTS, |x, y, k, col| {
        let p = &mut img.data[y * width + x];
        for c in 0..3 {
            p[c] = (p[c] as f32 + (col[c] as f32 - p[c] as f32) * k).round() as u8;
@@ -264,14 +303,14 @@ pub fn draw_watermark(img: &mut Rgba8, wm: &Watermark) {
 pub fn draw_watermark_deep(img: &mut DeepImage, wm: &Watermark) {
    let (width, trc) = (img.width, img.space.trc());
    match &mut img.samples {
-        DeepSamples::U16(v) => watermark_coverage(img.width, img.height, wm, |x, y, k, col| {
+        DeepSamples::U16(v) => watermark_coverage(img.width, img.height, wm, crate::fonts::CRAFT_FONTS, |x, y, k, col| {
            let i = (y * width + x) * 3;
            for c in 0..3 {
                let p = v[i + c] as f32;
                v[i + c] = (p + (col[c] as f32 * 257.0 - p) * k).round().clamp(0.0, 65535.0) as u16;
            }
        }),
-        DeepSamples::F32(v) => watermark_coverage(img.width, img.height, wm, |x, y, k, col| {
+        DeepSamples::F32(v) => watermark_coverage(img.width, img.height, wm, crate::fonts::CRAFT_FONTS, |x, y, k, col| {
            let i = (y * width + x) * 3;
            for c in 0..3 {
                let target = trc.decode(col[c] as f32 / 255.0);
@@ -282,9 +321,16 @@ pub fn draw_watermark_deep(img: &mut DeepImage, wm: &Watermark) {
 }

 /// Lay out `wm` on a `width × height` image and call `blend(x, y, coverage × opacity, colour)` for
-/// every covered pixel (shadow pass first).
-fn watermark_coverage(width: usize, height: usize, wm: &Watermark, mut blend_px: impl FnMut(usize, usize, f32, [u8; 3])) {
-    use ab_glyph::{Font, FontRef, PxScale, ScaleFont, point};
+/// every covered pixel (shadow pass first). `craft` is [`crate::fonts::CRAFT_FONTS`] (a parameter
+/// so tests can render without it).
+fn watermark_coverage(
+    width: usize,
+    height: usize,
+    wm: &Watermark,
+    craft: &'static [crate::fonts::CraftFont],
+    mut blend_px: impl FnMut(usize, usize, f32, [u8; 3]),
+) {
+    use ab_glyph::{Font, PxScale, ScaleFont, point};
    if !wm.image.trim().is_empty() {
        logo_coverage(width, height, wm, blend_px);
        return;
@@ -293,9 +339,13 @@ fn watermark_coverage(width: usize, height: usize, wm: &Watermark, mut blend_px:
    if text.is_empty() || width == 0 || height == 0 {
        return;
    }
-    let Ok(font) = FontRef::try_from_slice(WATERMARK_FONT) else { return };
-    let Ok(japanese) = FontRef::try_from_slice(WATERMARK_JAPANESE_FONT) else { return };
-    let fonts = [font, japanese];
+    let fonts = watermark_fonts(craft);
+    let Some(latin) = fonts.first() else { return };
+    let vertical_data: Vec<_> = if wm.vertical {
+        fonts.iter().map(|font| harfrust::FontRef::new(font.font_data()).ok().map(|face| harfrust::ShaperData::new(&face))).collect()
+    } else {
+        Vec::new()
+    };
    let short = width.min(height) as f32;
    let px = (wm.size.clamp(0.005, 0.5) * short).max(6.0);
    let mut glyphs = Vec::new();
@@ -319,6 +369,21 @@ fn watermark_coverage(width: usize, height: usize, wm: &Watermark, mut blend_px:
            prev = None;
            continue;
        }
+        if wm.vertical
+            && matches!(original as u32, 0x3000..=0x30FF | 0x3400..=0x9FFF | 0xFF01..=0xFF60)
+            && let Some(face) = fonts.iter().position(|font| font.glyph_id(original).0 != 0)
+            && let (Some(font), Some(Some(data))) = (fonts.get(face), vertical_data.get(face))
+        {
+            let left = columns.saturating_sub(column.saturating_add(1)) as f32 * px;
+            if let Some(glyph) = vertical_watermark_glyph(font, data, original, px, left, y)
+                && (glyph.id != font.glyph_id(original)
+                    || !matches!(original, '、' | '。' | 'ー' | '（' | '）' | '「' | '」' | '『' | '』' | '【' | '】'))
+            {
+                glyphs.push((face, glyph, None));
+                y += px;
+                continue;
+            }
+        }
        let vertical_form = match original {
            '、' => '︑',
            '。' => '︒',
@@ -333,9 +398,11 @@ fn watermark_coverage(width: usize, height: usize, wm: &Watermark, mut blend_px:
            '…' => '︙',
            other => other,
        };
-        let ch = if wm.vertical && fonts[1].glyph_id(vertical_form).0 != 0 { vertical_form } else { original };
-        let face = usize::from(fonts[0].glyph_id(ch).0 == 0);
-        let sf = fonts[face].as_scaled(PxScale::from(px));
+        let has = |font: &ab_glyph::FontRef<'_>, c: char| font.glyph_id(c).0 != 0;
+        let ch = if wm.vertical && fonts.iter().skip(1).any(|f| has(f, vertical_form)) { vertical_form } else { original };
+        // The first face with the glyph; Inter (its missing-glyph box) when none has it.
+        let face = fonts.iter().position(|f| has(f, ch)).unwrap_or(0);
+        let sf = fonts.get(face).unwrap_or(latin).as_scaled(PxScale::from(px));
        let id = sf.glyph_id(ch);
        if wm.vertical {
            let left = columns.saturating_sub(column.saturating_add(1)) as f32 * px;
@@ -544,12 +611,264 @@ impl Default for ExportOptions {
    }
 }

+/// The `app.export` params that are not export options: which photos, where to, a preset to start
+/// from, and the desktop app's background flag.
+pub const TARGET_PARAMS: &[&str] = &["id", "ids", "path", "dir", "preset", "background"];
+
+/// The export option params [`ExportOptions::from_json`] reads (and [`ExportOptions::to_json`] writes).
+pub const OPTION_PARAMS: &[&str] = &[
+    "format",
+    "quality",
+    "resize",
+    "longEdge",
+    "shortEdge",
+    "width",
+    "height",
+    "megapixels",
+    "percent",
+    "dontEnlarge",
+    "ppi",
+    "limitKb",
+    "sharpen",
+    "sharpenAmount",
+    "naming",
+    "startNumber",
+    "subfolder",
+    "conflict",
+    "tiffCompression",
+    "dngCompression",
+    "metadata",
+    "removeLocation",
+    "watermark",
+    "colorSpace",
+    "bitDepth",
+];
+
+/// The keys of a `watermark` object ([`Watermark`], camelCase).
+pub const WATERMARK_PARAMS: &[&str] = &["text", "vertical", "size", "opacity", "anchor", "inset", "color", "shadow", "image", "imageWidth"];
+
+/// Text height as a fraction of the short edge: the range the renderer draws without clamping.
+pub const WATERMARK_SIZE_RANGE: (f32, f32) = (0.005, 0.5);
+/// Margin as a fraction of the short edge.
+pub const WATERMARK_INSET_RANGE: (f32, f32) = (0.0, 0.4);
+/// A graphic's width as a fraction of the photo's width.
+pub const WATERMARK_IMAGE_WIDTH_RANGE: (f32, f32) = (0.01, 1.0);
+
+/// Levenshtein distance, for "did you mean" on a misspelled key (both inputs are short).
+fn edit_distance(a: &str, b: &str) -> usize {
+    let (a, b): (Vec<char>, Vec<char>) = (a.chars().collect(), b.chars().collect());
+    let mut prev: Vec<usize> = (0..=b.len()).collect();
+    for (i, ca) in a.iter().enumerate() {
+        let mut cur = vec![i + 1; b.len() + 1];
+        for (j, cb) in b.iter().enumerate() {
+            let sub = prev.get(j).copied().unwrap_or(0) + usize::from(ca != cb);
+            let del = prev.get(j + 1).copied().unwrap_or(0) + 1;
+            let ins = cur.get(j).copied().unwrap_or(0) + 1;
+            if let Some(c) = cur.get_mut(j + 1) {
+                *c = sub.min(del).min(ins);
+            }
+        }
+        prev = cur;
+    }
+    prev.last().copied().unwrap_or(0)
+}
+
+/// `unknown parameter \`k\``, naming the closest known key when one is near.
+fn unknown_key(what: &str, k: &str, known: &[&str]) -> String {
+    let near = known.iter().map(|n| (edit_distance(&k.to_ascii_lowercase(), &n.to_ascii_lowercase()), *n)).filter(|(d, _)| *d <= 2).min();
+    match near {
+        Some((_, n)) => format!("unknown {what} `{k}` (did you mean `{n}`?)"),
+        None => format!("unknown {what} `{k}` (one of {})", known.join(", ")),
+    }
+}
+
+/// A JSON integer (`92`; never `92.5` or `"92"`), as [`ExportOptions::from_json`] reads them.
+fn whole(v: &serde_json::Value) -> Option<i64> {
+    v.as_i64()
+}
+
 impl ExportOptions {
+    /// Stored export settings (a saved preset, `prefs.json ▸ lastExport`) with the keys an older or
+    /// newer version may have written and this one doesn't know dropped, also inside `watermark`.
+    /// [`ExportOptions::validate`] is strict about what a caller types; settings saved on disk are
+    /// not the caller's typo, and refusing them would make a preset or Export with Previous fail
+    /// for good after an update.
+    pub fn known_keys_only(p: &serde_json::Value) -> serde_json::Value {
+        let mut p = p.clone();
+        if let Some(o) = p.as_object_mut() {
+            o.retain(|k, _| OPTION_PARAMS.contains(&k.as_str()) || TARGET_PARAMS.contains(&k.as_str()));
+            if let Some(w) = o.get_mut("watermark").and_then(serde_json::Value::as_object_mut) {
+                w.retain(|k, _| WATERMARK_PARAMS.contains(&k.as_str()));
+            }
+        }
+        p
+    }
+
+    /// Strict [`ExportOptions::from_json`] for a command that is about to export (issue #181): an
+    /// unknown parameter or a value that cannot be read as what it is for is an error, never a
+    /// silent default. `app.export` targets (`id`, `ids`, `path`, `dir`, `preset`, `background`)
+    /// are accepted and left to the caller.
+    pub fn from_params(p: &serde_json::Value) -> crate::Result<Self> {
+        Self::validate("app.export", p)?;
+        Ok(Self::from_json(p))
+    }
+
+    /// Check `app.export` params for `cmd` (the command named in the error): every key must be an
+    /// export option ([`OPTION_PARAMS`]) or a target ([`TARGET_PARAMS`]), every value must be the
+    /// kind of thing its key takes, and a `watermark` object must hold only [`WATERMARK_PARAMS`]
+    /// with its sizes in range (issue #183). `null` means "not given", as a dropped key does.
+    pub fn validate(cmd: &str, p: &serde_json::Value) -> crate::Result<()> {
+        use serde_json::Value;
+        let bad = |msg: String| crate::cmd::bad(cmd, msg);
+        let Some(obj) = p.as_object() else { return Err(bad("params must be an object".into())) };
+        let known: Vec<&str> = OPTION_PARAMS.iter().chain(TARGET_PARAMS).copied().collect();
+        let int = |k: &str, v: &Value, lo: i64, hi: i64| -> crate::Result<i64> {
+            whole(v).filter(|i| (lo..=hi).contains(i)).ok_or_else(|| bad(format!("`{k}` must be an integer {lo}..{hi}")))
+        };
+        let num = |k: &str, v: &Value, lo: f64, hi: f64| -> crate::Result<f64> {
+            v.as_f64().filter(|f| f.is_finite() && (lo..=hi).contains(f)).ok_or_else(|| bad(format!("`{k}` must be a number {lo}..{hi}")))
+        };
+        fn string<'a>(cmd: &str, k: &str, v: &'a Value) -> crate::Result<&'a str> {
+            v.as_str().ok_or_else(|| crate::cmd::bad(cmd, format!("`{k}` must be a string")))
+        }
+        let boolean = |k: &str, v: &Value| -> crate::Result<bool> { v.as_bool().ok_or_else(|| bad(format!("`{k}` must be true or false"))) };
+        let one_of = |k: &str, v: &Value, options: &[&str]| -> crate::Result<()> {
+            let s = string(cmd, k, v)?;
+            if options.iter().any(|o| o.eq_ignore_ascii_case(s)) { Ok(()) } else { Err(bad(format!("`{k}` must be one of {}", options.join("|")))) }
+        };
+        for (k, v) in obj {
+            if v.is_null() {
+                continue;
+            }
+            match k.as_str() {
+                "format" => {
+                    if ExportFormat::parse(string(cmd, k, v)?).is_none() {
+                        return Err(bad(format!("`{k}` must be one of jpeg|png|tiff|webp|avif|dng|original")));
+                    }
+                }
+                "quality" => {
+                    int(k, v, 1, 100)?;
+                }
+                "ppi" => {
+                    int(k, v, 1, u16::MAX as i64)?;
+                }
+                "limitKb" => {
+                    int(k, v, 0, u32::MAX as i64)?;
+                }
+                "startNumber" => {
+                    int(k, v, 0, 999_999)?;
+                }
+                "bitDepth" => {
+                    if !matches!(whole(v), Some(8 | 10 | 16 | 32)) {
+                        return Err(bad(format!("`{k}` must be 8, 10, 16 or 32")));
+                    }
+                }
+                "longEdge" | "shortEdge" | "width" | "height" | "megapixels" | "percent" => {
+                    num(k, v, 0.0, 1.0e9)?;
+                }
+                "resize" => {
+                    let Some(r) = v.as_object() else { return Err(bad(format!("`{k}` must be an object {{mode, value, height?, dontEnlarge?}}"))) };
+                    if let Some(x) = r.keys().find(|x| !matches!(x.as_str(), "mode" | "value" | "height" | "dontEnlarge")) {
+                        return Err(bad(unknown_key("resize key", x, &["mode", "value", "height", "dontEnlarge"])));
+                    }
+                    serde_json::from_value::<Resize>(v.clone()).map_err(|e| bad(format!("`{k}`: {e}")))?;
+                }
+                "dontEnlarge" | "removeLocation" | "background" => {
+                    boolean(k, v)?;
+                }
+                "naming" | "subfolder" | "path" | "dir" | "preset" => {
+                    string(cmd, k, v)?;
+                }
+                "sharpen" => one_of(k, v, &["none", "screen", "matte", "glossy"])?,
+                "sharpenAmount" => one_of(k, v, &["low", "standard", "high"])?,
+                "conflict" => one_of(k, v, &["unique", "overwrite", "skip"])?,
+                "tiffCompression" => one_of(k, v, &["none", "lzw", "zip", "deflate"])?,
+                "dngCompression" => {
+                    serde_json::from_value::<DngCompression>(v.clone())
+                        .map_err(|_| bad(format!("`{k}` must be one of lossless|deflate|uncompressed")))?;
+                }
+                "metadata" => one_of(k, v, &["all", "allExceptCamera", "copyright", "none"])?,
+                "colorSpace" => {
+                    if OutputSpace::parse(string(cmd, k, v)?).is_none() {
+                        return Err(bad(format!("`{k}` must be one of srgb|displayP3|adobeRgb|proPhoto|rec2020")));
+                    }
+                }
+                "watermark" => Self::validate_watermark(cmd, v)?,
+                "id" => {
+                    int(k, v, 0, i64::MAX)?;
+                }
+                "ids" => {
+                    let ok = v.as_array().is_some_and(|a| a.iter().all(|x| x.is_u64()));
+                    if !ok {
+                        return Err(bad(format!("`{k}` must be an array of photo ids")));
+                    }
+                }
+                _ => return Err(bad(unknown_key("parameter", k, &known))),
+            }
+        }
+        Ok(())
+    }
+
+    /// A `watermark` value: text, or an object of [`WATERMARK_PARAMS`] (issue #183).
+    fn validate_watermark(cmd: &str, v: &serde_json::Value) -> crate::Result<()> {
+        use serde_json::Value;
+        let bad = |msg: String| crate::cmd::bad(cmd, msg);
+        let obj = match v {
+            Value::String(_) => return Ok(()),
+            Value::Object(o) => o,
+            _ => {
+                return Err(bad(
+                    "`watermark` must be text or an object {text, vertical, size, opacity, anchor, inset, color, shadow, image, imageWidth}".into(),
+                ));
+            }
+        };
+        let frac = |k: &str, v: &Value, (lo, hi): (f32, f32), unit: &str| -> crate::Result<()> {
+            match v.as_f64() {
+                Some(f) if f.is_finite() && (f64::from(lo)..=f64::from(hi)).contains(&f) => Ok(()),
+                _ => Err(bad(format!("`watermark.{k}` must be a number {lo}..{hi} ({unit})"))),
+            }
+        };
+        for (k, v) in obj {
+            if v.is_null() {
+                continue;
+            }
+            match k.as_str() {
+                "text" | "image" => {
+                    v.as_str().ok_or_else(|| bad(format!("`watermark.{k}` must be a string")))?;
+                }
+                "vertical" | "shadow" => {
+                    v.as_bool().ok_or_else(|| bad(format!("`watermark.{k}` must be true or false")))?;
+                }
+                "size" => frac(k, v, WATERMARK_SIZE_RANGE, "fraction of the short edge")?,
+                "opacity" => frac(k, v, (0.0, 1.0), "0 = invisible, 1 = solid")?,
+                "inset" => frac(k, v, WATERMARK_INSET_RANGE, "fraction of the short edge")?,
+                "imageWidth" => frac(k, v, WATERMARK_IMAGE_WIDTH_RANGE, "fraction of the photo's width")?,
+                "anchor" => {
+                    serde_json::from_value::<Anchor>(v.clone()).map_err(|_| {
+                        bad("`watermark.anchor` must be one of topLeft|top|topRight|left|center|right|bottomLeft|bottom|bottomRight".into())
+                    })?;
+                }
+                "color" => {
+                    let ok = v.as_array().is_some_and(|a| a.len() == 3 && a.iter().all(|c| matches!(whole(c), Some(0..=255))));
+                    if !ok {
+                        return Err(bad("`watermark.color` must be [r, g, b] with 0..255 each (sRGB)".into()));
+                    }
+                }
+                _ => return Err(bad(unknown_key("watermark key", k, WATERMARK_PARAMS))),
+            }
+        }
+        serde_json::from_value::<Watermark>(v.clone()).map(|_| ()).map_err(|e| bad(format!("`watermark`: {e}")))
+    }
+
    /// Read options from command params (`format`, `quality`, `limitKb`, `sharpen`, `sharpenAmount`,
    /// `naming`, `metadata`, `removeLocation`, `watermark`, `colorSpace`, `bitDepth`, `ppi`) and the
    /// size: one of `longEdge`, `shortEdge`, `width`, `height` (both = fit inside W × H),
    /// `megapixels`, `percent` (absent or 0 = full size), or a [`Resize`] object as `resize`; plus
    /// `dontEnlarge` (default true).
+    ///
+    /// Lenient: anything unknown or unreadable falls back to the default, which suits stored
+    /// prefs and dialog prefill. A command that is about to export uses
+    /// [`ExportOptions::from_params`], which validates first.
    pub fn from_json(p: &serde_json::Value) -> Self {
        use serde_json::Value;
        let d = Self::default();
@@ -1131,15 +1450,27 @@ pub fn export_batch(
 }

 /// Write an exported or rendered file on disk: its folder is created if needed, and the file is
-/// replaced atomically ([`lightcraft_catalog::safe_file::write_atomic`]: a temp file, synced, then
-/// renamed), so a failure part-way leaves any previous file intact and no truncated one. The
-/// native writer behind exports, renders and screenshots (app, CLI, MCP).
+/// replaced atomically ([`lightcraft_catalog::safe_file::write_atomic_nosync`]: a temp file
+/// renamed into place), so a failure part-way leaves any previous file intact and no truncated
+/// one. Not synced to disk (issue #134): an export can always be made again from the original.
+/// The native writer behind exports, renders and screenshots (app, CLI, MCP).
 pub fn write_file(path: &str, bytes: &[u8]) -> Result<(), String> {
+    write_with(path, bytes, false)
+}
+
+/// [`write_file`], synced to disk: for a written file that becomes a library photo (Edit a Copy)
+/// and so can't simply be exported again once the catalog points at it.
+pub fn write_file_durable(path: &str, bytes: &[u8]) -> Result<(), String> {
+    write_with(path, bytes, true)
+}
+
+fn write_with(path: &str, bytes: &[u8], durable: bool) -> Result<(), String> {
+    use lightcraft_catalog::safe_file::{write_atomic, write_atomic_nosync};
    let p = std::path::Path::new(path);
    if let Some(dir) = p.parent().filter(|d| !d.as_os_str().is_empty()) {
        std::fs::create_dir_all(dir).map_err(|e| format!("{}: {e}", dir.display()))?;
    }
-    lightcraft_catalog::safe_file::write_atomic(p, bytes).map_err(|e| format!("{path}: {e}"))
+    if durable { write_atomic(p, bytes) } else { write_atomic_nosync(p, bytes) }.map_err(|e| format!("{path}: {e}"))
 }

 /// The path of the sidecar with extension `ext` of the exported file `main`.
@@ -1334,21 +1665,89 @@ mod tests {
        assert!(ExportOptions::from_json(&serde_json::json!({"watermark": ""})).watermark.is_none());
    }

-    #[test]
-    fn japanese_watermarks_support_vertical_columns_and_legacy_defaults() {
-        use ab_glyph::Font;
-        let font = ab_glyph::FontRef::try_from_slice(WATERMARK_JAPANESE_FONT).unwrap();
-        for c in "日本語".chars() {
-            assert_ne!(font.glyph_id(c).0, 0);
-        }
-        let old = ExportOptions::from_json(&json!({"watermark": {"text": "日本語"}}));
-        assert!(!old.watermark.unwrap().vertical);
+    fn vertical_japanese() -> Watermark {
        let options =
            ExportOptions::from_json(&json!({"watermark": {"text": "日本語", "vertical": true, "size": 0.1, "shadow": false, "opacity": 1.0}}));
-        let wm = options.watermark.unwrap();
+        options.watermark.unwrap()
+    }
+
+    #[test]
+    fn japanese_watermark_options_and_legacy_defaults() {
+        let old = ExportOptions::from_json(&json!({"watermark": {"text": "日本語"}}));
+        assert!(!old.watermark.unwrap().vertical);
+        let wm = vertical_japanese();
        assert!(wm.vertical);
        let round: Watermark = serde_json::from_value(serde_json::to_value(&wm).unwrap()).unwrap();
        assert!(round.vertical);
+    }
+
+    /// Built without craft-fonts, a Japanese watermark still lays out and draws (Inter's
+    /// missing-glyph boxes), and Latin text is unaffected.
+    #[test]
+    fn watermarks_work_without_craft_fonts() {
+        assert_eq!(watermark_fonts(&[]).len(), 1, "Inter only");
+        for wm in [vertical_japanese(), Watermark { text: "LightCraft 日本語".into(), ..Watermark::default() }] {
+            let mut covered = 0usize;
+            watermark_coverage(400, 300, &wm, &[], |_, _, k, _| covered += usize::from(k > 0.0));
+            assert!(covered > 0, "{:?} draws something", wm.text);
+        }
+    }
+
+    #[test]
+    fn biz_ud_vertical_watermarks_place_punctuation_at_the_top_right() {
+        use ab_glyph::Font;
+        let Some(entry) = crate::fonts::CRAFT_FONTS.iter().find(|f| f.family == "BIZ UDMincho") else {
+            eprintln!("skipped: built without BIZ UDMincho from craft-fonts");
+            return;
+        };
+        let font = ab_glyph::FontRef::try_from_slice(entry.bytes).unwrap();
+        // BIZ UDMincho has no Unicode presentation-form characters: the old fallback drew 、。.
+        assert_eq!(font.glyph_id('︑').0, 0);
+        assert_eq!(font.glyph_id('︒').0, 0);
+        let data = harfrust::ShaperData::new(&harfrust::FontRef::new(entry.bytes).unwrap());
+        for ch in ['、', '。'] {
+            let glyph = vertical_watermark_glyph(&font, &data, ch, 100.0, 0.0, 0.0).unwrap();
+            assert_ne!(glyph.id, font.glyph_id(ch), "the font's vertical alternate for {ch}");
+            let rect = font.outline_glyph(glyph).unwrap().px_bounds();
+            assert!(rect.min.x > 50.0 && rect.max.y < 50.0, "{ch} in the upper right: {rect:?}");
+        }
+        let craft = Box::leak(
+            vec![crate::fonts::CraftFont { family: entry.family, style: entry.style, scripts: entry.scripts, bytes: entry.bytes }].into_boxed_slice(),
+        );
+        let wm = Watermark {
+            text: "、。".into(),
+            vertical: true,
+            size: 0.1,
+            anchor: Anchor::TopLeft,
+            inset: 0.0,
+            shadow: false,
+            opacity: 1.0,
+            ..Default::default()
+        };
+        let mut pixels = Vec::new();
+        watermark_coverage(400, 300, &wm, craft, |x, y, k, _| {
+            if k > 0.5 {
+                pixels.push((x, y));
+            }
+        });
+        assert!(!pixels.is_empty());
+        for (x, y) in pixels {
+            assert!(x > 15 && y % 30 < 15, "actual export coverage at the upper right of the 30 px cell: {x}, {y}");
+        }
+    }
+
+    #[test]
+    fn japanese_watermarks_support_vertical_columns() {
+        use ab_glyph::Font;
+        let fonts = watermark_fonts(crate::fonts::CRAFT_FONTS);
+        if fonts.len() < 2 {
+            eprintln!("skipped: built without CRAFT_FONTS_DIR, so there is no Japanese watermark face");
+            return;
+        }
+        for c in "日本語の文字".chars() {
+            assert!(fonts[1..].iter().any(|f| f.glyph_id(c).0 != 0), "a craft-fonts face has {c}");
+        }
+        let wm = vertical_japanese();
        let mut img = Rgba8::new(400, 300);
        img.data.fill([0, 0, 0, 255]);
        draw_watermark(&mut img, &wm);
@@ -1665,4 +2064,99 @@ mod tests {
            Err(e) => assert!(e.contains("not available"), "{e}"),
        }
    }
+
+    /// Issue #181: a command about to export refuses what `from_json` would silently default —
+    /// unknown keys (naming the nearest known one) and values of the wrong kind or range.
+    #[test]
+    fn export_params_are_validated() {
+        use serde_json::json;
+        let err = |p: serde_json::Value| ExportOptions::from_params(&p).err().map(|e| e.to_string()).unwrap_or_default();
+        let e = err(json!({"longEdgee": 400}));
+        assert!(e.starts_with("invalid parameters for `app.export`: unknown parameter `longEdgee` (did you mean `longEdge`?)"), "{e}");
+        assert!(err(json!({"qualty": 5})).contains("did you mean `quality`"));
+        assert!(err(json!({"longEdge": "banana"})).contains("`longEdge` must be a number"));
+        assert!(err(json!({"quality": 0})).contains("`quality` must be an integer 1..100"));
+        assert!(err(json!({"quality": "5"})).contains("`quality` must be an integer"));
+        assert!(err(json!({"quality": 92.5})).contains("`quality` must be an integer"));
+        assert!(err(json!({"sharpen": "lots"})).contains("`sharpen` must be one of none|screen|matte|glossy"));
+        assert!(err(json!({"format": "bmp"})).contains("`format` must be one of"));
+        assert!(err(json!({"bitDepth": 12})).contains("`bitDepth` must be 8, 10, 16 or 32"));
+        assert!(err(json!({"colorSpace": "cmyk"})).contains("`colorSpace` must be one of"));
+        assert!(err(json!({"dontEnlarge": "no"})).contains("`dontEnlarge` must be true or false"));
+        assert!(err(json!({"resize": {"mode": "longEdge", "valeu": 10}})).contains("did you mean `value`"));
+        assert!(err(json!({"resize": {"mode": "diagonal", "value": 10}})).contains("`resize`:"));
+        assert!(err(json!({"ids": [1, "x"]})).contains("`ids` must be an array of photo ids"));
+        assert!(err(json!("jpeg")).contains("params must be an object"));
+        assert!(
+            ExportOptions::validate("export.savePreset", &json!({"qualty": 5}))
+                .unwrap_err()
+                .to_string()
+                .starts_with("invalid parameters for `export.savePreset`")
+        );
+        // everything the presets, the dialog, Export with Previous and `render --opt` send passes
+        for p in builtin_presets() {
+            ExportOptions::from_params(&p.params).unwrap_or_else(|e| panic!("{}: {e}", p.name));
+        }
+        let full = ExportOptions {
+            resize: Some(Resize::default()),
+            limit_kb: Some(500),
+            watermark: Some(Watermark { text: "©".into(), ..Default::default() }),
+            bit_depth: Some(16),
+            ..Default::default()
+        };
+        let mut j = full.to_json();
+        for (k, v) in [
+            ("dir", json!("/tmp/out")),
+            ("background", json!(true)),
+            ("preset", json!("x")),
+            ("ids", json!([1, 2])),
+            ("id", json!(1)),
+            ("path", json!("a.jpg")),
+        ] {
+            j[k] = v;
+        }
+        assert_eq!(ExportOptions::from_params(&j).unwrap(), full);
+        assert_eq!(ExportOptions::from_params(&ExportOptions::default().to_json()).unwrap(), ExportOptions::default());
+        // null is "not given", as a dropped key is
+        ExportOptions::from_params(&json!({"quality": 92, "longEdge": null, "watermark": null})).unwrap();
+    }
+
+    /// Issue #183: the `watermark` object's keys, kinds and ranges are checked (and documented in
+    /// the `app.export` param string), instead of unknown keys passing and sizes clamping silently.
+    #[test]
+    fn watermark_params_are_validated() {
+        use serde_json::json;
+        let err = |w: serde_json::Value| ExportOptions::from_params(&json!({"watermark": w})).err().map(|e| e.to_string()).unwrap_or_default();
+        assert!(
+            err(json!(5))
+                .contains("`watermark` must be text or an object {text, vertical, size, opacity, anchor, inset, color, shadow, image, imageWidth}")
+        );
+        assert!(
+            err(json!({"text": "x", "bogus": 1}))
+                .contains("unknown watermark key `bogus` (one of text, vertical, size, opacity, anchor, inset, color, shadow, image, imageWidth)")
+        );
+        assert!(err(json!({"text": "x", "sizee": 0.1})).contains("did you mean `size`"));
+        for size in [json!(3), json!(0.5001), json!(0), json!("big")] {
+            let e = err(json!({"text": "x", "size": size}));
+            assert!(e.contains("`watermark.size` must be a number 0.005..0.5 (fraction of the short edge)"), "{size}: {e}");
+        }
+        assert!(err(json!({"text": "x", "opacity": 1.5})).contains("`watermark.opacity` must be a number 0..1"));
+        assert!(err(json!({"text": "x", "inset": -0.1})).contains("`watermark.inset` must be a number 0..0.4"));
+        assert!(err(json!({"image": "logo.png", "imageWidth": 2})).contains("`watermark.imageWidth` must be a number 0.01..1"));
+        assert!(err(json!({"text": "x", "anchor": "middle"})).contains("`watermark.anchor` must be one of"));
+        assert!(err(json!({"text": "x", "color": [255, 255]})).contains("`watermark.color` must be [r, g, b]"));
+        assert!(err(json!({"text": "x", "color": [255, 255, 256]})).contains("`watermark.color`"));
+        assert!(err(json!({"text": "x", "vertical": "yes"})).contains("`watermark.vertical` must be true or false"));
+        assert!(err(json!({"text": 7})).contains("`watermark.text` must be a string"));
+        // the documented shapes pass and read as before
+        let o = ExportOptions::from_params(&json!({"watermark": "© me"})).unwrap();
+        assert_eq!(o.watermark.map(|w| w.text).as_deref(), Some("© me"));
+        let w = json!({"text": "日本語", "vertical": true, "size": 0.1, "opacity": 0.5, "anchor": "topLeft", "inset": 0.05, "color": [0, 0, 0], "shadow": false, "image": "", "imageWidth": 0.3});
+        let wm = ExportOptions::from_params(&json!({"watermark": w})).unwrap().watermark.unwrap();
+        assert!((wm.size - 0.1).abs() < 1e-6 && wm.vertical && wm.anchor == Anchor::TopLeft && wm.color == [0, 0, 0] && !wm.shadow);
+        assert_eq!(ExportOptions::from_params(&json!({"watermark": {"text": "x", "size": 0.5}})).unwrap().watermark.map(|w| w.size), Some(0.5));
+        // the Export dialog's sliders (1–15 % size, 5–100 % opacity, 2–100 % width) stay inside the accepted ranges
+        assert!(WATERMARK_SIZE_RANGE.0 <= 0.01 && WATERMARK_SIZE_RANGE.1 >= 0.15);
+        assert!(WATERMARK_IMAGE_WIDTH_RANGE.0 <= 0.02 && WATERMARK_IMAGE_WIDTH_RANGE.1 >= 1.0);
+    }
 }
@@ -38,12 +38,14 @@ fn meta_of(m: &lightcraft_meta::Metadata) -> (Meta, Option<String>) {
        copyright_url: m.copyright_url.clone().unwrap_or_default(),
        creator: m.artist.clone().unwrap_or_default(),
        keywords: m.keywords.clone(),
+        regions: m.regions.clone(),
    };
    (meta, m.capture_time.as_ref().map(|d| d.to_iso()))
 }

-/// Lens corrections embedded in a DNG's `OpcodeList3` (`WarpRectilinear`, `FixVignetteRadial`), re-expressed for
-/// the default-cropped, EXIF-oriented image. These are the only "profile" corrections LightCraft applies.
+/// Lens corrections embedded in a raw's `OpcodeList3` (`WarpRectilinear`, `FixVignetteRadial`: a DNG's own, or the
+/// raw reader's equivalent of the camera's correction, e.g. Panasonic / Leica RW2 distortion), re-expressed for the
+/// default-cropped, EXIF-oriented image. These are the only "profile" corrections LightCraft applies.
 pub fn embedded_lens(raw: &lightcraft_raw::RawInfo) -> Option<lightcraft_develop::EmbeddedLens> {
    use lightcraft_develop::{EmbeddedLens, EmbeddedVignette, EmbeddedWarp};
    use lightcraft_geom::Point;
@@ -86,10 +88,6 @@ pub fn embedded_lens(raw: &lightcraft_raw::RawInfo) -> Option<lightcraft_develop
    Some(lightcraft_pipeline::optics::reorient_lens(&lens, raw.orientation, cw, ch))
 }

-fn is_lens_opcode(op: &lightcraft_raw::Opcode) -> bool {
-    matches!(op, lightcraft_raw::Opcode::WarpRectilinear { .. } | lightcraft_raw::Opcode::FixVignetteRadial { .. })
-}
-
 fn ext_upper(name: &str) -> String {
    std::path::Path::new(name).extension().map(|e| e.to_string_lossy().to_uppercase()).unwrap_or_default()
 }
@@ -101,9 +99,9 @@ pub fn probe_bytes(name: &str, bytes: &[u8]) -> Result<ProbeInfo, String> {
    let m = lightcraft_meta::extract(bytes);
    let (meta, captured) = meta_of(&m);
    if lightcraft_raw::probe(bytes).is_some() {
-        let raw = match lightcraft_raw::probe_info(bytes) {
+        let raw = match lightcraft_raw::probe_info(bytes).map_err(|e| preview_reason(bytes, e)) {
            Ok(r) => r,
-            Err(lightcraft_raw::RawError::Unsupported(why)) => {
+            Err(Ok(why)) => {
                // a raw variant we can't decode yet: describe it from its embedded preview
                let (w, h) = embedded_preview_size(bytes).ok_or(format!("unsupported raw ({why}) without an embedded preview"))?;
                return Ok(ProbeInfo {
@@ -121,7 +119,7 @@ pub fn probe_bytes(name: &str, bytes: &[u8]) -> Result<ProbeInfo, String> {
                    ..Default::default()
                });
            }
-            Err(e) => return Err(e.to_string()),
+            Err(Err(e)) => return Err(e),
        };
        let (mut w, mut h) = (raw.crop.width.max(1) as u32, raw.crop.height.max(1) as u32);
        if w <= 1 || h <= 1 {
@@ -131,7 +129,9 @@ pub fn probe_bytes(name: &str, bytes: &[u8]) -> Result<ProbeInfo, String> {
            std::mem::swap(&mut w, &mut h);
        }
        let (t, tint) = xy_to_temp_tint(lightcraft_raw::color::as_shot_white_xy_of(&raw));
-        let as_shot_wb = Some((t.round(), tint.round()));
+        // Vendor RGB multipliers do not identify an absolute illuminant without camera calibration.
+        let relative = crate::camera_preview::file_local_look(raw.format) && !lightcraft_raw::color::has_matrix(&raw.color);
+        let as_shot_wb = Some(if relative { (6500.0, 0.0) } else { (t.round(), tint.round()) });
        let embedded_lens = embedded_lens(&raw);
        return Ok(ProbeInfo {
            embedded_lens,
@@ -179,6 +179,21 @@ pub fn probe_bytes(name: &str, bytes: &[u8]) -> Result<ProbeInfo, String> {
    })
 }

+/// Why a raw that failed to decode should show its embedded preview instead (`Ok`), or the error
+/// to report (`Err`). Variants we can't decode yet always fall back. So does any CR3 error: the CRX
+/// decoder is verified on few bodies, and every CR3 opened from its embedded JPEG before it existed.
+/// So does any other failure of a recognised raw (damaged or oversized raw data, unreadable TIFF
+/// structure): its preview may still be intact. Only a file that is not a raw reports an error.
+fn preview_reason(bytes: &[u8], e: lightcraft_raw::RawError) -> Result<String, String> {
+    use lightcraft_raw::RawError;
+    match e {
+        RawError::Unsupported(why) => Ok(why),
+        e if lightcraft_raw::probe(bytes) == Some(lightcraft_raw::RawFormat::Cr3) => Ok(format!("CR3 {e}")),
+        RawError::NotRaw => Err(RawError::NotRaw.to_string()),
+        e => Ok(e.to_string()),
+    }
+}
+
 /// Sensor clip level (normalised) for highlight reconstruction.
 const HIGHLIGHT_CLIP: f32 = 0.99;

@@ -213,21 +228,25 @@ pub fn load_vec(bytes: Vec<u8>, max_edge: usize) -> Result<(Rgb32f, SourceInfo),

 fn load_bytes_now(bytes: std::borrow::Cow<'_, [u8]>, max_edge: usize) -> Result<(Rgb32f, SourceInfo), String> {
    if lightcraft_raw::probe(&bytes).is_some() {
-        let mut raw = match lightcraft_raw::decode(&bytes) {
+        let mut raw = match lightcraft_raw::decode(&bytes).map_err(|e| preview_reason(&bytes, e)) {
            Ok(r) => r,
-            Err(lightcraft_raw::RawError::Unsupported(why)) => {
+            Err(Ok(why)) => {
                // show the camera's embedded JPEG (rendered, not raw) until the variant is supported
                return load_embedded_preview(&bytes, max_edge).ok_or(format!("unsupported raw ({why}) without an embedded preview"));
            }
-            Err(e) => return Err(e.to_string()),
+            Err(Err(e)) => return Err(e),
        };
-        drop(bytes);
-        // Embedded lens corrections are applied by the pipeline ("Enable Profile Corrections"), not baked in.
+        // Embedded lens corrections are applied by the pipeline ("Enable Profile Corrections"), not baked in
+        // (removed before the camera look's binned sensor proxy too, which needs an empty `OpcodeList3`).
        let lens = embedded_lens(&raw.info());
-        raw.opcodes.list3.retain(|op| !is_lens_opcode(op));
+        raw.opcodes.list3.retain(|op| !op.is_lens_correction());
+        let xy = lightcraft_raw::color::as_shot_white_xy(&raw);
+        let t = lightcraft_raw::color::camera_transform(&raw, xy);
+        let camera_look = crate::camera_preview::fit_preview(&raw, &bytes, &t);
+        drop(bytes);
        // Previews and thumbnails bin the mosaic straight to (about) the size they need; only
        // larger levels (exports, 1:1) demosaic the whole sensor.
-        let t0 = std::time::Instant::now();
+        let t0 = web_time::Instant::now();
        let binned = match bin_factor(&raw, max_edge) {
            Some(k) => raw.develop_binned(k, HIGHLIGHT_CLIP).map_err(|e| e.to_string())?,
            None => None,
@@ -242,21 +261,28 @@ fn load_bytes_now(bytes: std::borrow::Cow<'_, [u8]>, max_edge: usize) -> Result<
        // the samples aren't needed any more (the colour model below reads only the tags)
        raw.data = lightcraft_raw::RawData::U16(Vec::new());
        let mut stages = vec![("develop", t0.elapsed())];
-        let xy = lightcraft_raw::color::as_shot_white_xy(&raw);
-        let t = lightcraft_raw::color::camera_transform(&raw, xy);
        stages.push(("transform", t0.elapsed()));
        lightcraft_raw::highlight::reconstruct(&mut img, t.wb, HIGHLIGHT_CLIP);
        stages.push(("highlights", t0.elapsed()));
-        let m = t.matrix.to_f32();
+        let m = camera_look.as_ref().map(|p| p.matrix.mul(&t.matrix)).unwrap_or(t.matrix).to_f32();
+        let hue_sat = camera_look.as_ref().and_then(|p| p.hue_sat.as_ref()).and_then(crate::camera_preview::HueSat::new);
        let gain = 2f32.powf(t.baseline_exposure as f32);
        let wb = t.wb;
+        // A DNG's own profile look (hue/saturation map, look table), DNG spec chapter 6.
+        let tables = lightcraft_raw::profile::ProfileTables::new(&raw.color.profile, lightcraft_raw::color::illuminant_weight(&raw.color, xy));
        img.map_in_place(|p| {
            let c = [p[0] * wb[0], p[1] * wb[1], p[2] * wb[2]];
-            [
-                ((m[0][0] * c[0] + m[0][1] * c[1] + m[0][2] * c[2]) * gain).max(0.0),
-                ((m[1][0] * c[0] + m[1][1] * c[1] + m[1][2] * c[2]) * gain).max(0.0),
-                ((m[2][0] * c[0] + m[2][1] * c[1] + m[2][2] * c[2]) * gain).max(0.0),
-            ]
+            let rgb = [
+                m[0][0] * c[0] + m[0][1] * c[1] + m[0][2] * c[2],
+                m[1][0] * c[0] + m[1][1] * c[1] + m[1][2] * c[2],
+                m[2][0] * c[0] + m[2][1] * c[1] + m[2][2] * c[2],
+            ];
+            let rgb = match &tables {
+                Some(tables) => tables.apply(rgb, gain),
+                None => rgb.map(|v| v * gain),
+            };
+            // after the baseline exposure, as when it was fitted
+            hue_sat.as_ref().map_or(rgb, |h| h.apply(rgb)).map(|v| v.max(0.0))
        });
        stages.push(("colour", t0.elapsed()));
        let img = fit(&img, max_edge, max_edge, Filter::Box);
@@ -276,7 +302,10 @@ fn load_bytes_now(bytes: std::borrow::Cow<'_, [u8]>, max_edge: usize) -> Result<
            eprintln!("[profile] raw source {}×{} (max {max_edge}, ms after decode): {}", img.width, img.height, parts.join(", "));
        }
        let (temp, tint) = xy_to_temp_tint(xy);
-        return Ok((img, SourceInfo { raw: true, as_shot_temp: temp.round(), as_shot_tint: tint.round(), lens }));
+        let relative = crate::camera_preview::file_local_look(raw.format) && t.matrix_is_fallback;
+        let camera_tone = camera_look.as_ref().map(|p| p.tone).or_else(|| raw.color.profile.tone_curve.as_ref().and_then(dng_tone_curve));
+        let (temp, tint) = if relative { (6500.0, 0.0) } else { (temp.round(), tint.round()) };
+        return Ok((img, SourceInfo { raw: true, as_shot_temp: temp, as_shot_tint: tint, lens, relative_wb: relative, camera_tone }));
    }
    let d = lightcraft_codecs::decode(&bytes, lightcraft_codecs::DecodeOptions::fit(max_edge as u32, max_edge as u32)).map_err(|e| e.to_string())?;
    drop(bytes);
@@ -285,6 +314,17 @@ fn load_bytes_now(bytes: std::borrow::Cow<'_, [u8]>, max_edge: usize) -> Result<
    Ok((img.into_oriented(Orientation::from_exif(d.orientation)), SourceInfo::default()))
 }

+/// A DNG `ProfileToneCurve` (linear in, linear out, 1.0 = white after exposure compensation) as the
+/// finish stage's camera tone curve: 32 knots, log-spaced over 12 stops below white; above white
+/// the camera tone's shoulder continues it.
+pub(crate) fn dng_tone_curve(curve: &lightcraft_raw::profile::ToneCurve) -> Option<lightcraft_pipeline::tone::CameraTone> {
+    let knots: [[f32; 2]; 32] = std::array::from_fn(|i| {
+        let x = 2f32.powf(-12.0 + 12.0 * i as f32 / 31.0);
+        [x, curve.eval(x).min(0.9995)]
+    });
+    lightcraft_pipeline::tone::CameraTone::new(knots)
+}
+
 /// Orientation for an embedded preview: its own EXIF orientation when it has one, else the raw file's.
 fn preview_orientation(raw_bytes: &[u8], jpeg_orientation: u16) -> Orientation {
    if jpeg_orientation > 1 {
@@ -293,9 +333,38 @@ fn preview_orientation(raw_bytes: &[u8], jpeg_orientation: u16) -> Orientation {
    lightcraft_meta::extract(raw_bytes).orientation.unwrap_or(Orientation::Normal)
 }

+/// What stands in for a raw file we can't decode: its largest embedded JPEG, else, for a TIFF-based
+/// raw, the file's own first image when the TIFF reader can show it (a reduced RGB copy: the only
+/// preview some containers carry). Returns image bytes for [`lightcraft_codecs::decode`].
+fn stand_in_image(bytes: &[u8]) -> Option<std::borrow::Cow<'_, [u8]>> {
+    if let Some(jpeg) = lightcraft_raw::embedded_preview(bytes) {
+        return Some(std::borrow::Cow::Owned(jpeg));
+    }
+    let undecodable = lightcraft_raw::probe(bytes).is_some_and(|f| !f.is_supported());
+    (undecodable && lightcraft_codecs::sniff(bytes).is_some_and(|f| f == lightcraft_codecs::Format::Tiff))
+        .then_some(std::borrow::Cow::Borrowed(bytes))
+}
+
+/// Shared colour interpretation for quick previews, unsupported RAW fallback and camera-look fitting.
+pub(crate) fn decode_raw_preview(bytes: &[u8], opts: lightcraft_codecs::DecodeOptions) -> Option<lightcraft_codecs::Decoded> {
+    let jpeg = stand_in_image(bytes)?;
+    // the colour space is a property of the JPEG; a TIFF stand-in is read by the TIFF reader
+    let is_jpeg = matches!(jpeg, std::borrow::Cow::Owned(_));
+    match lightcraft_raw::embedded_preview_color_space(bytes).filter(|_| is_jpeg) {
+        Some(space) => {
+            let space = match space {
+                lightcraft_raw::PreviewColorSpace::Srgb => lightcraft_codecs::NamedSpace::Srgb,
+                lightcraft_raw::PreviewColorSpace::AdobeRgb => lightcraft_codecs::NamedSpace::AdobeRgb,
+            };
+            lightcraft_codecs::decode_jpeg_with_fallback(&jpeg, opts, space).ok()
+        }
+        None => lightcraft_codecs::decode(&jpeg, opts).ok(),
+    }
+}
+
 /// Oriented size of the embedded preview of a raw file.
 fn embedded_preview_size(bytes: &[u8]) -> Option<(u32, u32)> {
-    let jpeg = lightcraft_raw::embedded_preview(bytes)?;
+    let jpeg = stand_in_image(bytes)?;
    let d = lightcraft_codecs::decode(&jpeg, lightcraft_codecs::DecodeOptions::fit(64, 64)).ok()?;
    let (mut w, mut h) = (d.source_width, d.source_height);
    if preview_orientation(bytes, d.orientation).swaps_axes() {
@@ -306,8 +375,7 @@ fn embedded_preview_size(bytes: &[u8]) -> Option<(u32, u32)> {

 /// The embedded preview of a raw file as a working-space image no larger than `max_edge`, oriented.
 pub fn load_embedded_preview(bytes: &[u8], max_edge: usize) -> Option<(Rgb32f, SourceInfo)> {
-    let jpeg = lightcraft_raw::embedded_preview(bytes)?;
-    let d = lightcraft_codecs::decode(&jpeg, lightcraft_codecs::DecodeOptions::fit(max_edge as u32, max_edge as u32)).ok()?;
+    let d = decode_raw_preview(bytes, lightcraft_codecs::DecodeOptions::fit(max_edge as u32, max_edge as u32))?;
    let img = d.to_working();
    let img = if img.width.max(img.height) > max_edge { fit(&img, max_edge, max_edge, Filter::Mitchell) } else { img };
    Some((img.oriented(preview_orientation(bytes, d.orientation)), SourceInfo::default()))
@@ -316,8 +384,7 @@ pub fn load_embedded_preview(bytes: &[u8], max_edge: usize) -> Option<(Rgb32f, S
 /// The embedded preview of a raw file for display (sRGB, oriented, no larger than `max_edge`): the
 /// loupe and grid show it until the raw itself has been developed ([`crate::media::QuickJob`]).
 pub fn embedded_preview_srgb(bytes: &[u8], max_edge: usize) -> Option<lightcraft_raster::Rgba8> {
-    let jpeg = lightcraft_raw::embedded_preview(bytes)?;
-    let mut d = lightcraft_codecs::decode(&jpeg, lightcraft_codecs::DecodeOptions::fit(max_edge as u32, max_edge as u32)).ok()?;
+    let mut d = decode_raw_preview(bytes, lightcraft_codecs::DecodeOptions::fit(max_edge as u32, max_edge as u32))?;
    if d.image.width.max(d.image.height) > max_edge {
        d.image = fit(&d.image, max_edge, max_edge, Filter::Box);
        d.alpha = None;
@@ -375,6 +442,131 @@ mod tests {
    use super::*;
    use lightcraft_codecs::{ChromaSubsampling, EncodeImage, EncodeMeta, Samples, encode_jpeg};

+    /// Luminance (from linear RGB) minus its 9 × 9 local mean: tone differences between a render and a camera JPEG
+    /// mostly cancel, edges remain.
+    fn detail(w: usize, h: usize, lum: impl Fn(usize, usize) -> f32) -> Vec<f32> {
+        let l: Vec<f32> = (0..w * h).map(|i| lum(i % w, i / w)).collect();
+        let mut out = vec![0.0; w * h];
+        for y in 0..h {
+            for x in 0..w {
+                let (x0, x1, y0, y1) = (x.saturating_sub(4), (x + 5).min(w), y.saturating_sub(4), (y + 5).min(h));
+                let m = (y0..y1).flat_map(|yy| (x0..x1).map(move |xx| (xx, yy))).map(|(xx, yy)| l[yy * w + xx]).sum::<f32>();
+                out[y * w + x] = l[y * w + x] - m / ((x1 - x0) * (y1 - y0)) as f32;
+            }
+        }
+        out
+    }
+
+    /// The integer shift (within ±`r` px) of the `p × p` patch of `a` at `(x, y)` that best matches `b`, with its
+    /// normalised cross-correlation, or `None` when the patch has too little detail to tell.
+    fn patch_shift(a: &[f32], b: &[f32], w: usize, (x, y): (usize, usize), p: usize, r: i64) -> Option<((i64, i64), f32)> {
+        let pa: Vec<f32> = (0..p * p).map(|i| a[(y + i / p) * w + x + i % p]).collect();
+        let na = pa.iter().map(|v| v * v).sum::<f32>().sqrt();
+        if na < 1e-3 * p as f32 {
+            return None;
+        }
+        let mut best = (f32::MIN, (0, 0));
+        for dy in -r..=r {
+            for dx in -r..=r {
+                let (bx, by) = (x as i64 + dx, y as i64 + dy);
+                let (mut dot, mut nb) = (0.0f32, 0.0f32);
+                for i in 0..p {
+                    for j in 0..p {
+                        let v = b[(by as usize + i) * w + bx as usize + j];
+                        dot += pa[i * p + j] * v;
+                        nb += v * v;
+                    }
+                }
+                let c = dot / (na * nb.sqrt()).max(1e-12);
+                if c > best.0 {
+                    best = (c, (dx, dy));
+                }
+            }
+        }
+        Some((best.1, best.0))
+    }
+
+    /// Issue #256: public Panasonic / Leica raws (skipped without the corpus) are corrected for distortion the way the
+    /// camera corrected its own JPEG (tag 0x0119): at the corners of the frame, the render with "Enable Profile
+    /// Corrections" lines up with the embedded JPEG within 2 px at 640 px, while the uncorrected render of the wide
+    /// lenses is far off. A file shot with the camera's correction off (DMC-GH1) carries no correction.
+    #[test]
+    fn corpus_rw2_distortion_matches_the_camera_jpeg() {
+        let dir = std::env::var_os("LIGHTCRAFT_CORPUS")
+            .map(std::path::PathBuf::from)
+            .unwrap_or_else(|| std::path::Path::new(env!("CARGO_MANIFEST_DIR")).join("../../corpus"))
+            .join("raw");
+        let Ok(gh1) = std::fs::read(dir.join("rw2-panasonic-gh1.rw2")) else {
+            eprintln!("skip: {} absent", dir.display());
+            return;
+        };
+        assert_eq!(probe_bytes("gh1.rw2", &gh1).unwrap().embedded_lens, None, "correction off: nothing to apply");
+        assert_eq!(load_bytes(&gh1, 320).unwrap().1.lens, None);
+
+        // (file, how far off (px) the uncorrected corners are at the least, if they match within ±R at all)
+        let files = [
+            ("rw2-panasonic-fz1000m2-4x3.rw2", 8), // 9.1 mm, ~13 % at the corners
+            ("rwl-leica-dlux7.rwl", 8),            // 10.9 mm, ~13 %
+            ("rw2-panasonic-gx80.rw2", 8),         // 14 mm, ~8 %
+            ("rw2-panasonic-gh6.rw2", 3),          // 20 mm, ~1.6 %
+            ("rw2-panasonic-s9.rw2", 3),           // 45 mm, 3 % zoom after the correction
+            ("rw2-panasonic-g9.rw2", 0),           // 40 mm, ~0.5 %
+        ];
+        const EDGE: usize = 640;
+        const P: usize = 64;
+        const R: i64 = 12;
+        for (name, off_at_least) in files {
+            let bytes = std::fs::read(dir.join(name)).unwrap();
+            let probed = probe_bytes(name, &bytes).unwrap();
+            assert!(probed.embedded_lens.is_some_and(|l| l.warp.is_some()), "{name}: no distortion correction read");
+            let (src, info) = load_bytes(&bytes, 2 * EDGE).unwrap();
+            assert_eq!(info.lens, probed.embedded_lens, "{name}: probe and decode disagree");
+            // Convert to DNG keeps it: the same correction, as the DNG's own `WarpRectilinear`
+            let dng = lightcraft_raw::write_dng(&lightcraft_raw::decode(&bytes).unwrap(), &Default::default()).unwrap();
+            assert_eq!(probe_bytes("x.dng", &dng).unwrap().embedded_lens, probed.embedded_lens, "{name}: lost in the DNG");
+            let mut s = lightcraft_develop::DevelopSettings::default();
+            let render = |s: &lightcraft_develop::DevelopSettings| {
+                lightcraft_pipeline::render(&src, &info, s, &lightcraft_pipeline::RenderRequest::fit(EDGE, EDGE)).image
+            };
+            let before = render(&s);
+            s.optics.lens_profile = true;
+            let after = render(&s);
+            let (w, h) = (after.width, after.height);
+            assert_eq!((before.width, before.height), (w, h));
+            // the camera JPEG shows the whole sensor; a render in an in-camera aspect ratio is its centre
+            let (cam, _) = load_embedded_preview(&bytes, 4 * EDGE).unwrap();
+            let (cw, ch) = (cam.width as f64, cam.height as f64);
+            let (sw, sh) = if cw / ch > w as f64 / h as f64 { (ch * w as f64 / h as f64, ch) } else { (cw, cw * h as f64 / w as f64) };
+            let cam = cam.crop(((cw - sw) / 2.0).round() as usize, ((ch - sh) / 2.0).round() as usize, sw.round() as usize, sh.round() as usize);
+            let cam = lightcraft_raster::resample::resize(&cam, w, h, Filter::Mitchell);
+            let lin = |v: u8| (v as f32 / 255.0).powf(2.2);
+            let lum8 = |im: &lightcraft_raster::Rgba8, x: usize, y: usize| {
+                let p = im.data[y * im.width + x];
+                0.3 * lin(p[0]) + 0.6 * lin(p[1]) + 0.1 * lin(p[2])
+            };
+            let reference = detail(w, h, |x, y| {
+                let p = cam.data[y * w + x];
+                0.3 * p[0] + 0.6 * p[1] + 0.1 * p[2]
+            });
+            let (db, da) = (detail(w, h, |x, y| lum8(&before, x, y)), detail(w, h, |x, y| lum8(&after, x, y)));
+            let m = R as usize + 4;
+            let corners = [(m, m), (w - m - P, m), (m, h - m - P), (w - m - P, h - m - P)];
+            let mut measured = 0;
+            for c in corners {
+                let Some(((dx, dy), ca)) = patch_shift(&da, &reference, w, c, P, R) else { continue };
+                measured += 1;
+                assert!(dx.abs() <= 2 && dy.abs() <= 2 && ca >= 0.5, "{name}: corrected corner {c:?} off by ({dx}, {dy}) px, ncc {ca}");
+                if off_at_least > 0
+                    && let Some(((bx, by), cb)) = patch_shift(&db, &reference, w, c, P, R)
+                {
+                    let off = bx.abs().max(by.abs()) >= off_at_least || cb < 0.3;
+                    assert!(off, "{name}: uncorrected corner {c:?} already within ({bx}, {by}) px, ncc {cb}");
+                }
+            }
+            assert!(measured >= 2, "{name}: only {measured} corners with detail");
+        }
+    }
+
    /// A CR3-shaped file (not decodable yet) whose only content is a `PRVW` preview box.
    fn cr3_with_preview(w: u32, h: u32) -> Vec<u8> {
        let px: Vec<u8> = (0..w * h).flat_map(|i| [(i % 251) as u8, 128, 200]).collect();
@@ -390,6 +582,78 @@ mod tests {
        b
    }

+    /// [`cr3_with_preview`] plus a full-size CRX raw track whose `CMP1` coding header is garbage:
+    /// the container parses, the raw data doesn't (`RawError::Corrupt`, not `Unsupported`).
+    fn cr3_with_corrupt_raw(w: u32, h: u32) -> Vec<u8> {
+        let bx = |kind: &[u8; 4], body: &[u8]| [&((body.len() + 8) as u32).to_be_bytes()[..], kind, body].concat();
+        let mut craw = vec![0u8; 82];
+        craw[24..26].copy_from_slice(&(w as u16).to_be_bytes());
+        craw[26..28].copy_from_slice(&(h as u16).to_be_bytes());
+        craw.extend(bx(b"CMP1", &[0xff; 4]));
+        let mut stsd = vec![0, 0, 0, 0, 0, 0, 0, 1];
+        stsd.extend(bx(b"CRAW", &craw));
+        let stsz = [0u32, 16, 1].map(u32::to_be_bytes).concat();
+        let co64 = [&[0u8, 0, 0, 0, 0, 0, 0, 1][..], &0u64.to_be_bytes()].concat();
+        let stbl = [bx(b"stsd", &stsd), bx(b"stsz", &stsz), bx(b"co64", &co64)].concat();
+        let trak = bx(b"trak", &bx(b"mdia", &bx(b"minf", &bx(b"stbl", &stbl))));
+        let preview = cr3_with_preview(w, h);
+        [&preview[..24], &bx(b"moov", &trak), &preview[24..]].concat()
+    }
+
+    /// A CR3 whose raw data fails to decode, for any reason, still opens from its embedded JPEG:
+    /// CR3s did before the CRX decoder, which is verified on few bodies (PR #279 review).
+    #[test]
+    fn corrupt_cr3_falls_back_to_embedded_preview() {
+        let b = cr3_with_corrupt_raw(48, 32);
+        let err = lightcraft_raw::decode(&b).expect_err("the fixture's raw data is corrupt");
+        assert!(!matches!(err, lightcraft_raw::RawError::Unsupported(_)), "{err}");
+        let p = probe_bytes("x.cr3", &b).unwrap();
+        assert_eq!((p.width, p.height, p.kind, p.format.as_str()), (48, 32, MediaKind::Raw, "CR3"));
+        assert!(p.preview_only.is_some_and(|why| why.contains("CR3")));
+        let (img, src) = load_bytes(&b, 24).unwrap();
+        assert_eq!((img.width, img.height), (24, 16));
+        assert!(!src.raw);
+        // other formats still report a corrupt file as an error
+        let mut dng = crate::tests_xmp::synthetic_dng_with(None, Default::default());
+        dng.truncate(dng.len() / 2);
+        assert!(load_bytes(&dng, 24).is_err());
+    }
+
+    /// Issue #138: a DNG's own profile look (hue/saturation map, look table, tone curve) is
+    /// applied when it's developed — Lightroom-converted DNGs rendered flat and muted without it.
+    #[test]
+    fn dng_profile_look_is_applied() {
+        use lightcraft_raw::profile::{HsvTable, ProfileLook, ToneCurve};
+        let plain = crate::tests_xmp::synthetic_dng_with(None, Default::default());
+        let mut raw = lightcraft_raw::decode(&plain).unwrap();
+        let sat = |img: &Rgb32f| {
+            img.data.iter().map(|p| (p[0].max(p[1]).max(p[2]) - p[0].min(p[1]).min(p[2])) / p[0].max(p[1]).max(p[2]).max(1e-6)).sum::<f32>()
+                / img.data.len() as f32
+        };
+        let (before, info) = load_bytes(&plain, 64).unwrap();
+        assert!(sat(&before) > 0.05, "the synthetic scene is coloured");
+        assert!(info.camera_tone.is_none());
+        // a map that removes all saturation, and a tone curve
+        let grey = HsvTable { hue_divisions: 4, sat_divisions: 2, val_divisions: 1, data: vec![[0.0, 0.0, 1.0]; 8], srgb_value: false };
+        raw.color.profile =
+            ProfileLook { hue_sat_map: [Some(grey), None], look_table: None, tone_curve: ToneCurve::from_tag(&[0.0, 0.0, 0.18, 0.3, 1.0, 1.0]) };
+        let with = lightcraft_raw::write_dng(&raw, &Default::default()).unwrap();
+        let (after, info) = load_bytes(&with, 64).unwrap();
+        assert!(sat(&after) < 1e-3, "saturation {} → {}", sat(&before), sat(&after));
+        // a saturation-only map keeps brightness roughly (HSV value is kept in ProPhoto RGB)
+        let mean = |img: &Rgb32f| img.data.iter().map(|p| p[0].max(p[1]).max(p[2])).sum::<f32>() / img.data.len() as f32;
+        assert!((0.8..1.1).contains(&(mean(&after) / mean(&before))), "{} vs {}", mean(&after), mean(&before));
+        let tone = info.camera_tone.expect("the DNG tone curve becomes the camera tone");
+        assert!((tone.apply(0.18) - 0.3).abs() < 0.01, "{}", tone.apply(0.18));
+        // a look table alone changes the render too (applied after exposure)
+        raw.color.profile = ProfileLook {
+            look_table: Some(HsvTable { hue_divisions: 1, sat_divisions: 2, val_divisions: 1, data: vec![[0.0, 1.0, 0.5]; 2], srgb_value: false }),
+            ..Default::default()
+        };
+        let (dim, _) = load_bytes(&lightcraft_raw::write_dng(&raw, &Default::default()).unwrap(), 64).unwrap();
+        assert!((mean(&dim) / mean(&before) - 0.5).abs() < 0.02, "{} vs {}", mean(&dim), mean(&before));
+    }
+
    #[test]
    fn unsupported_raw_falls_back_to_embedded_preview() {
        let b = cr3_with_preview(48, 32);
@@ -458,6 +722,84 @@ mod tests {
        let _ = std::fs::remove_dir_all(&dir);
    }

+    /// A raw whose TIFF shell holds only a small RGB image (IFD0) next to a private block, as Exif
+    /// declares a picture 25x its size.
+    fn tiff_shell(w: u32, h: u32, shell: bool) -> Vec<u8> {
+        use lightcraft_tiff::{IfdBuilder, ImageData, TiffWriter, Value, tags as t};
+        let mut ifd0 = IfdBuilder::new();
+        ifd0.set(t::IMAGE_WIDTH, Value::Long(vec![w]));
+        ifd0.set(t::IMAGE_LENGTH, Value::Long(vec![h]));
+        ifd0.set(t::BITS_PER_SAMPLE, Value::Short(vec![8, 8, 8]));
+        ifd0.set(t::SAMPLES_PER_PIXEL, Value::Short(vec![3]));
+        ifd0.set(t::PHOTOMETRIC, Value::Short(vec![2]));
+        ifd0.set(t::COMPRESSION, Value::Short(vec![1]));
+        let px: Vec<u8> = (0..w * h).flat_map(|i| [(i % 251) as u8, 128, 200]).collect();
+        ifd0.set_image(ImageData::Strips { rows_per_strip: h, strips: vec![px] });
+        ifd0.set_child(
+            t::EXIF_IFD,
+            IfdBuilder::new().with(t::PIXEL_X_DIMENSION, Value::Long(vec![w * 25])).with(t::PIXEL_Y_DIMENSION, Value::Long(vec![h * 25])),
+        );
+        let mut b = TiffWriter::default().write(&[ifd0]).unwrap();
+        if shell {
+            b.extend(std::iter::repeat_n(0x5au8, (w * h * 625 / 8) as usize + 100));
+        }
+        b
+    }
+
+    /// A TIFF raw whose only image is a small thumbnail used to open as a plain image of that size
+    /// ("a 150 MP file renders 296x220"), with nothing saying so. Now it is recognised as a raw we can't
+    /// decode: preview only, with the reason, still showing that image.
+    #[test]
+    fn thumbnail_only_tiff_raw_is_preview_only_not_a_plain_image() {
+        let b = tiff_shell(24, 16, true);
+        let p = probe_bytes("IMG_0001.IIQ", &b).unwrap();
+        assert_eq!((p.kind, p.format.as_str(), p.width, p.height), (MediaKind::Raw, "IIQ", 24, 16));
+        let why = p.preview_only.expect("marked preview only");
+        assert!(why.contains("600x400") && why.contains("24x16"), "{why}");
+        let (img, src) = load_bytes(&b, 12).unwrap();
+        assert_eq!((img.width, img.height, src.raw), (12, 8, false));
+        assert!(embedded_preview_srgb(&b, 12).is_some());
+        // the same pixels without the private block are a small ordinary image
+        let plain = probe_bytes("small.tif", &tiff_shell(24, 16, false)).unwrap();
+        assert_eq!((plain.kind, plain.preview_only, plain.width, plain.height), (MediaKind::Image, None, 24, 16));
+        assert!(lightcraft_raw::probe(&tiff_shell(24, 16, false)).is_none());
+    }
+
+    /// Recognised raw containers we don't decode (Minolta MRW here: the preview's first byte is
+    /// overwritten in the file) import as preview only with the JPEG's size, instead of failing.
+    #[test]
+    fn undecodable_container_with_a_preview_imports_as_preview_only() {
+        let px: Vec<u8> = (0..40 * 30).flat_map(|i| [(i % 251) as u8, 128, 200]).collect();
+        let mut jpeg = encode_jpeg(&EncodeImage::new(40, 30, 3, Samples::U8(&px)), 90, ChromaSubsampling::S444, &EncodeMeta::default()).unwrap();
+        jpeg[0] = 0x02;
+        let mut f = b"\0MRM\0\x01\0\0".to_vec();
+        f.extend(std::iter::repeat_n(0x11u8, 300));
+        f.extend_from_slice(&jpeg);
+        f.extend(std::iter::repeat_n(0x22u8, 300));
+        let p = probe_bytes("A.MRW", &f).unwrap();
+        assert_eq!((p.kind, p.format.as_str(), p.width, p.height), (MediaKind::Raw, "MRW", 40, 30));
+        assert!(p.preview_only.is_some_and(|w| w.contains("Mrw")));
+        let (img, src) = load_bytes(&f, 20).unwrap();
+        assert_eq!((img.width, img.height, src.raw), (20, 15, false));
+        // without a JPEG: a clear error
+        let e = probe_bytes("A.MRW", b"\0MRM\0\x01\0\0 nothing here").unwrap_err();
+        assert!(e.contains("without an embedded preview"), "{e}");
+    }
+
+    /// Any failure of a recognised raw (not only an unsupported variant) can fall back to its preview;
+    /// CR3 keeps its own wording.
+    #[test]
+    fn decode_failures_of_recognised_raws_may_fall_back_to_the_preview() {
+        use lightcraft_raw::RawError;
+        let cr3 = b"\0\0\0\x18ftypcrx \0\0\0\x01";
+        assert_eq!(preview_reason(b"x", RawError::Unsupported("x".into())), Ok("x".to_string()));
+        assert!(preview_reason(b"x", RawError::Corrupt("bad strip".into())).is_ok_and(|w| w.contains("bad strip")));
+        assert!(preview_reason(b"x", RawError::Limit("too big")).is_ok());
+        assert!(preview_reason(b"x", RawError::Tiff(lightcraft_tiff::TiffError::MissingTag(256))).is_ok());
+        assert!(preview_reason(b"x", RawError::NotRaw).is_err());
+        assert!(preview_reason(cr3, RawError::Corrupt("bad".into())).is_ok_and(|w| w.starts_with("CR3 ")));
+    }
+
    #[test]
    fn quick_jobs_show_embedded_previews_then_cached_renders() {
        use crate::media::QuickSource;
@@ -0,0 +1,115 @@
+//! Fonts from the optional craft-fonts build input (storytold/craft-fonts).
+//!
+//! Built with `CRAFT_FONTS_DIR=<craft-fonts checkout>`, [`CRAFT_FONTS`] holds every font in its
+//! manifest (today: the Japanese and Simplified-Chinese UI and document fonts); otherwise it is
+//! empty and LightCraft uses only its own bundled fonts (Inter). Both the egui UI and the export
+//! watermark renderer read it from here. See craftrules `standards/fonts.md`.
+
+/// A font from the optional craft-fonts build input (empty unless built with `CRAFT_FONTS_DIR`).
+pub struct CraftFont {
+    pub family: &'static str,
+    pub style: &'static str,
+    /// ISO 15924 scripts the font is for, e.g. `"Jpan"`.
+    pub scripts: &'static [&'static str],
+    pub bytes: &'static [u8],
+}
+
+include!(concat!(env!("OUT_DIR"), "/craft_fonts.rs"));
+
+impl CraftFont {
+    /// Whether the font is meant for `script` (ISO 15924, e.g. `"Jpan"`).
+    pub fn covers(&self, script: &str) -> bool {
+        self.scripts.contains(&script)
+    }
+
+    /// Mincho (serif) faces, the preferred Japanese faces for document-like text.
+    pub fn is_mincho(&self) -> bool {
+        self.family.contains("Mincho")
+    }
+
+    /// Whether the font can stand in for `script`: it is meant for it, or — until craft-fonts has a
+    /// Traditional Chinese face — it is a Simplified Chinese face, which carries the Traditional
+    /// characters too (with mainland glyph forms; still closer than the Japanese faces).
+    pub fn serves(&self, script: &str) -> bool {
+        self.covers(script) || (script == "Hant" && self.covers("Hans"))
+    }
+}
+
+/// The craft-fonts faces for Japanese, in `fonts`' order (empty without craft-fonts).
+pub fn japanese(fonts: &'static [CraftFont]) -> impl Iterator<Item = &'static CraftFont> {
+    fonts.iter().filter(|f| f.covers("Jpan"))
+}
+
+/// The craft-fonts faces for any CJK script: what any CJK text needs, regardless of language.
+pub fn cjk(fonts: &'static [CraftFont]) -> impl Iterator<Item = &'static CraftFont> {
+    fonts.iter().filter(|f| f.scripts.iter().any(|script| is_cjk_script(script)))
+}
+
+/// Whether an ISO 15924 script is written with Han, kana or hangul characters (Unicode's CJK
+/// scripts), which Inter has no glyphs for.
+pub fn is_cjk_script(script: &str) -> bool {
+    matches!(script, "Hans" | "Hant" | "Jpan" | "Kore" | "Hang" | "Hani" | "Bopo" | "Yiii" | "Nshu" | "Tang")
+}
+
+/// The craft-fonts faces to fall back on for `script`, in preference order: the faces of that script
+/// first (for `style` when asked), then every other CJK face. One CJK face list serves every
+/// language, but Han characters are shared between them: a Chinese reader must get the Chinese
+/// forms and a Japanese reader the Japanese ones, so the active language's own script comes first.
+/// Empty without craft-fonts.
+pub fn cjk_fallback<'a>(fonts: &'a [CraftFont], script: &str, style: &str) -> Vec<&'a CraftFont> {
+    let mut faces: Vec<&CraftFont> = fonts.iter().filter(|font| covers_cjk(font)).collect();
+    faces.sort_by_key(|font| {
+        (
+            // The language's own script first. A face dedicated to the script is preferred over a
+            // multi-script face (Noto Sans CJK SC claims `Hans,Latn`; a Japanese face claims `Jpan`).
+            !font.serves(script),
+            font.scripts.len() != 1,
+            font.family != "BIZ UDPGothic",
+            font.style != style,
+            font.is_mincho(),
+        )
+    });
+    faces
+}
+
+/// Whether the font is for any CJK script.
+fn covers_cjk(font: &CraftFont) -> bool {
+    font.scripts.iter().any(|script| is_cjk_script(script))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn craft_fonts_are_well_formed_or_absent() {
+        if CRAFT_FONTS.is_empty() {
+            eprintln!("built without CRAFT_FONTS_DIR: no craft-fonts to check");
+            return;
+        }
+        for f in CRAFT_FONTS {
+            assert!(!f.family.is_empty() && !f.style.is_empty() && !f.scripts.is_empty(), "{}", f.family);
+            assert!(ab_glyph::FontRef::try_from_slice(f.bytes).is_ok(), "{} {} parses", f.family, f.style);
+        }
+        assert!(japanese(CRAFT_FONTS).next().is_some(), "craft-fonts carries Japanese faces");
+    }
+
+    /// Each language's own faces come first, so shared Han keeps the language's forms, and Latin
+    /// text still reaches Inter before any CJK fallback.
+    #[test]
+    fn a_language_gets_its_own_script_first() {
+        static FACES: &[CraftFont] = &[
+            CraftFont { family: "BIZ UDPGothic", style: "Regular", scripts: &["Jpan", "Latn"], bytes: &[] },
+            CraftFont { family: "Noto Sans CJK SC", style: "Regular", scripts: &["Hans", "Latn"], bytes: &[] },
+            CraftFont { family: "BIZ UDMincho", style: "Regular", scripts: &["Jpan", "Latn"], bytes: &[] },
+        ];
+        let first = |script: &str| cjk_fallback(FACES, script, "Regular").first().map(|f| f.family);
+        assert_eq!(first("Hans"), Some("Noto Sans CJK SC"));
+        assert_eq!(first("Jpan"), Some("BIZ UDPGothic"));
+        // No Traditional Chinese face yet: the Chinese face stands in before the Japanese ones.
+        assert_eq!(first("Hant"), Some("Noto Sans CJK SC"));
+        // Every CJK face is still offered to every language.
+        assert_eq!(cjk_fallback(FACES, "Hans", "Regular").len(), 3);
+        assert_eq!(cjk_fallback(&[], "Hans", "Regular").len(), 0);
+    }
+}
@@ -56,6 +56,9 @@ pub(crate) enum Fault {
    Corrupt,
    /// Removing the source fails (as on a read-only card).
    FailRemove,
+    /// Each copy takes a little longer and notes the thread it ran on ([`copy_threads`]), to see
+    /// an import's copies run side by side.
+    Slow,
 }

 #[cfg(test)]
@@ -69,6 +72,21 @@ pub(crate) fn inject(f: Fault) {
    FAULT.with(|c| c.set(f));
 }

+/// The calling thread's injected fault (tests only), for the workers it starts to inherit.
+#[cfg(test)]
+pub(crate) fn injected_fault() -> Fault {
+    FAULT.with(|c| c.get())
+}
+
+/// The threads copies made under [`Fault::Slow`] ran on (tests only).
+#[cfg(test)]
+static COPY_THREADS: std::sync::Mutex<Vec<std::thread::ThreadId>> = std::sync::Mutex::new(Vec::new());
+
+#[cfg(test)]
+pub(crate) fn copy_threads() -> Vec<std::thread::ThreadId> {
+    COPY_THREADS.lock().unwrap_or_else(std::sync::PoisonError::into_inner).clone()
+}
+
 fn injected(f: Fault) -> bool {
    #[cfg(test)]
    {
@@ -171,9 +189,15 @@ pub(crate) fn place(src: &Path, dir: &Path, name: &str) -> Result<Placed, String

 /// Import → **Copy**: copy `src` into `dir` as `name` (-1, -2… when taken) with the same checks as
 /// a move's copy — a new file (never overwriting one, even one that appears meanwhile), synced to
-/// disk and compared byte for byte with the source; a bad copy is removed and reported, so a card
-/// is never wiped on the strength of it. Returns the new path.
-pub(crate) fn copy_new(src: &Path, dir: &Path, name: &str) -> Result<PathBuf, String> {
+/// disk and verified; a bad copy is removed and reported, so a card is never wiped on the strength
+/// of it. Returns the new path.
+///
+/// `expect` is the content hash the import's probe computed from its full read of the source
+/// ([`lightcraft_preview::hash_bytes`]): the copy is read back and checked against it, which spares
+/// a third read of the card (issue #134). It also catches a source that changed since the probe
+/// (whose recorded metadata and hash would be stale). Without one the copy is compared byte for
+/// byte with the source.
+pub(crate) fn copy_new(src: &Path, dir: &Path, name: &str, expect: Option<lightcraft_preview::Hash128>) -> Result<PathBuf, String> {
    fs::create_dir_all(dir).map_err(|e| format!("{}: {e}", dir.display()))?;
    let (stem, ext) = match name.rsplit_once('.') {
        Some((s, e)) if !s.is_empty() => (s.to_string(), format!(".{e}")),
@@ -181,7 +205,7 @@ pub(crate) fn copy_new(src: &Path, dir: &Path, name: &str) -> Result<PathBuf, St
    };
    for i in 0..100_000u32 {
        let d = if i == 0 { dir.join(name) } else { dir.join(format!("{stem}-{i}{ext}")) };
-        match copy_verified(src, &d) {
+        match copy_verified(src, &d, expect) {
            Ok(()) => return Ok(d),
            Err(e) if e.kind() == io::ErrorKind::AlreadyExists => continue,
            Err(e) => return Err(format!("copy {}: {e} (nothing was imported from it; the original is untouched)", src.display())),
@@ -262,12 +286,14 @@ fn link_or_copy(src: &Path, dst: &Path) -> io::Result<()> {
            Err(_) => {}
        }
    }
-    copy_verified(src, dst)
+    // Move keeps the byte-for-byte comparison: the source is deleted on the strength of it
+    copy_verified(src, dst, None)
 }

-/// Copy into a new file, sync it to disk and compare it with the original; on any failure the
-/// partial copy is removed.
-fn copy_verified(src: &Path, dst: &Path) -> io::Result<()> {
+/// Copy into a new file, sync it to disk and verify it: against `expect` (the probe's hash of the
+/// source) when given, else byte for byte against the source. On any failure the partial copy is
+/// removed.
+pub(crate) fn copy_verified(src: &Path, dst: &Path, expect: Option<lightcraft_preview::Hash128>) -> io::Result<()> {
    let mut out = OpenOptions::new().write(true).create_new(true).open(dst)?;
    let r = (|| {
        let mut inp = File::open(src)?;
@@ -276,6 +302,11 @@ fn copy_verified(src: &Path, dst: &Path) -> io::Result<()> {
            return Err(io::Error::other("write failed (injected)"));
        }
        io::copy(&mut inp, &mut out)?;
+        #[cfg(test)]
+        if injected(Fault::Slow) {
+            COPY_THREADS.lock().unwrap_or_else(std::sync::PoisonError::into_inner).push(std::thread::current().id());
+            std::thread::sleep(std::time::Duration::from_millis(30));
+        }
        if injected(Fault::Corrupt) {
            out.write_all(b"!")?;
        }
@@ -283,10 +314,14 @@ fn copy_verified(src: &Path, dst: &Path) -> io::Result<()> {
        if let Ok(m) = fs::metadata(src).and_then(|m| m.modified()) {
            let _ = out.set_modified(m);
        }
-        if !same_bytes(src, dst)? {
-            return Err(io::Error::other("the copy differs from the original"));
+        match expect {
+            Some(h) if hash_file(dst)? != h => {
+                Err(io::Error::other("the copy differs from the original as it was read for the import (a bad copy, or the file changed meanwhile)"))
+            }
+            Some(_) => Ok(()),
+            None if !same_bytes(src, dst)? => Err(io::Error::other("the copy differs from the original")),
+            None => Ok(()),
        }
-        Ok(())
    })();
    drop(out);
    if r.is_err() {
@@ -295,6 +330,20 @@ fn copy_verified(src: &Path, dst: &Path) -> io::Result<()> {
    r
 }

+/// [`lightcraft_preview::hash_bytes`] of a file's content, read in chunks.
+fn hash_file(path: &Path) -> io::Result<lightcraft_preview::Hash128> {
+    let mut f = File::open(path)?;
+    let mut h = lightcraft_preview::Hasher128::new();
+    let mut buf = vec![0u8; 1 << 20];
+    loop {
+        let n = fill(&mut f, &mut buf)?;
+        if n == 0 {
+            return Ok(h.finish());
+        }
+        h.update(buf.get(..n).unwrap_or(&[]));
+    }
+}
+
 /// Do two files hold the same bytes?
 pub(crate) fn same_bytes(a: &Path, b: &Path) -> io::Result<bool> {
    if fs::metadata(a)?.len() != fs::metadata(b)?.len() {
@@ -10,6 +10,9 @@
 //! run them off the UI thread.
 #![forbid(unsafe_code)]

+pub mod availability;
+mod camera_preview;
+pub mod camera_profiles;
 pub mod cmd;
 pub mod crs;
 pub mod crs_masks;
@@ -17,10 +20,16 @@ pub mod demo;
 pub mod devices;
 pub mod export;
 pub mod files;
+pub mod fonts;
 pub mod guard;
 pub mod import;
 mod import_move;
 pub mod library;
+mod lightroom_archive;
+pub mod lightroom_catalog;
+pub mod lightroom_job;
+mod lightroom_sqlite;
+pub mod logging;
 pub mod media;
 pub mod memory;
 pub mod merge;
@@ -29,18 +38,21 @@ pub mod preset_import;
 pub mod preset_luminar;
 pub mod presets;
 pub mod rename;
+pub mod segment;
 pub mod sidecar;
 pub mod smart;
 mod view;
+pub mod walk;

 use std::sync::Arc;

 pub use cmd::{CommandInfo, CommandSpec, command_specs, find_command};
+pub use fonts::{CRAFT_FONTS, CraftFont};
 use lightcraft_catalog::{Catalog, Filter, Op, PhotoId, Sort};
 use lightcraft_develop::DevelopSettings;
 pub use media::{RenderJob, SourceLevel};
 use serde_json::Value;
-pub use view::{Browse, FilterChip, LibrarySource, Selection, filter_chips};
+pub use view::{Browse, FilterChip, LibrarySource, Selection, SelectionState, filter_chips};
 pub use {lightcraft_catalog as catalog, lightcraft_develop as develop, lightcraft_gpu as gpu, lightcraft_pipeline as pipeline};

 #[derive(Debug, thiserror::Error)]
@@ -76,6 +88,27 @@ pub struct UndoEntry {
    pub folder: Option<FolderMove>,
 }

+/// The one photo an undo step changes, when it changes exactly one through its edit, rating, flag,
+/// label, metadata or versions (`depth` bounds nested batches).
+fn single_photo(op: &Op, depth: usize) -> Option<PhotoId> {
+    match op {
+        Op::SetDevelop { id, .. }
+        | Op::SetRating { id, .. }
+        | Op::SetFlag { id, .. }
+        | Op::SetLabel { id, .. }
+        | Op::SetMeta { id, .. }
+        | Op::SetVersions { id, .. }
+        | Op::SetHistory { id, .. }
+        | Op::PushHistory { id, .. } => Some(*id),
+        Op::Batch { ops } if depth < 8 => {
+            let mut ids = ops.iter().map(|o| single_photo(o, depth + 1));
+            let first = ids.next()??;
+            ids.all(|id| id == Some(first)).then_some(first)
+        }
+        _ => None,
+    }
+}
+
 /// A folder renamed or moved on disk as part of an undo step.
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub struct FolderMove {
@@ -121,10 +154,16 @@ pub struct Session {
    pub undo: Vec<UndoEntry>,
    pub redo: Vec<UndoEntry>,
    pub interaction: Option<Interaction>,
+    /// Set by a command whose change must not rewrite the photo's XMP sidecar even with auto-write on
+    /// (a catalog-only edit of data the sidecar writer does not emit); consumed when the command ends.
+    pub(crate) skip_auto_write: bool,
    /// Copied develop settings (partial JSON) for Paste.
    pub clipboard: Option<Value>,
    /// The folder on disk the [`LibrarySource::Folder`] view browses.
    pub browse: Option<Browse>,
+    /// The folder the [`LibrarySource::LibraryFolder`] view shows: the library's photos imported
+    /// from it and from the folders inside it.
+    pub library_folder: Option<String>,
    /// Copied metadata (`photo.copyMetadata`): photo.setMeta params.
    pub meta_clipboard: Option<Value>,
    /// The photo that was active before the current one (Paste Settings from Previous).
@@ -146,10 +185,14 @@ pub struct Session {
    depth: u32,
    /// Selected mask (Masking panel), by mask id.
    pub active_mask: Option<u32>,
+    /// AI masks (SAM 3): the model and the last photo prepared for it.
+    pub segmenter: segment::Segmenter,
    /// Selected spot (Remove panel), by index into the active photo's spots.
    pub active_spot: Option<usize>,
    /// The persistent library this session writes to (`None` = in-memory only).
    pub library: Option<library::Library>,
+    /// Identity of current library opening; refreshed only after a successful open.
+    pub(crate) library_identity: Arc<()>,
    /// XMP sidecar preferences (persisted with the library).
    pub xmp: sidecar::XmpPrefs,
    /// Parameters of the last export (`app.export` params, minus targets), persisted in prefs.json.
@@ -219,9 +262,11 @@ impl Session {
            undo: Vec::new(),
            redo: Vec::new(),
            interaction: None,
+            skip_auto_write: false,
            clipboard: None,
            meta_clipboard: None,
            browse: None,
+            library_folder: None,
            previous_active: None,
            copy_groups: lightcraft_develop::SettingsGroup::default_copy(),
            presets: presets::builtin(),
@@ -233,8 +278,10 @@ impl Session {
            clock: Box::new(|| "2026-09-30T12:00:00".to_string()),
            depth: 0,
            active_mask: None,
+            segmenter: segment::Segmenter::default(),
            active_spot: None,
            library: None,
+            library_identity: Arc::new(()),
            xmp: sidecar::XmpPrefs::default(),
            last_export: None,
            export_presets: Vec::new(),
@@ -272,11 +319,22 @@ impl Session {
        (spec.enabled)(self).map_err(|why| EngineError::Disabled(id.to_string(), why))?;
        let empty = Value::Object(Default::default());
        let params = if params.is_null() { &empty } else { params };
+        self.run_command(id, spec.journal.then_some(params), |s| (spec.run)(s, params))
+    }
+
+    /// Run `f` as command `id` with what [`Session::execute`] does around every command: the
+    /// panic guard, auto versions, XMP sidecar auto-write and the durable save (a failed save is
+    /// `NotSaved`). Not journaled. The app's import task commits its batches this way.
+    pub fn execute_fn(&mut self, id: &str, f: impl FnOnce(&mut Session) -> Result<Value>) -> Result<Value> {
+        self.run_command(id, None, f)
+    }
+
+    fn run_command(&mut self, id: &str, journal: Option<&Value>, f: impl FnOnce(&mut Session) -> Result<Value>) -> Result<Value> {
        let log_start = self.pending_log.len();
        let was_active = self.active();
        self.depth += 1;
        // last-resort guard: a panic in a command is that command's error, not a crash
-        let r = guard::catch(&format!("`{id}`"), || (spec.run)(self, params)).unwrap_or_else(|e| Err(EngineError::Other(e)));
+        let r = guard::catch(&format!("`{id}`"), || f(self)).unwrap_or_else(|e| Err(EngineError::Other(e)));
        self.depth -= 1;
        if self.depth == 0 && was_active.is_some() && self.active() != was_active {
            self.previous_active = was_active;
@@ -284,14 +342,20 @@ impl Session {
                self.auto_version(left);
            }
        }
-        if r.is_ok() && spec.journal && self.depth == 0 {
+        if r.is_ok()
+            && let Some(params) = journal
+            && self.depth == 0
+        {
            self.journal.push((id.to_string(), params.clone()));
            if self.journal.len() > 10_000 {
                self.journal.drain(..1000);
            }
        }
-        if r.is_ok() && self.depth == 0 && self.xmp.auto_write && self.interaction.is_none() && self.pending_log.len() > log_start {
-            self.auto_write_sidecars(&self.pending_log[log_start..]);
+        if self.depth == 0 {
+            let skip = std::mem::take(&mut self.skip_auto_write);
+            if r.is_ok() && !skip && self.xmp.auto_write && self.interaction.is_none() && self.pending_log.len() > log_start {
+                self.auto_write_sidecars(&self.pending_log[log_start..]);
+            }
        }
        if self.depth == 0 && self.library.is_some() {
            // Make the command durable before reporting success. When the command's own records
@@ -393,6 +457,7 @@ impl Session {
                return Err(err);
            }
        };
+        self.show_undone(&e.op);
        self.pending_log.push(e.op);
        self.redo.push(UndoEntry { label: e.label.clone(), op: redo, folder: e.folder.as_ref().map(FolderMove::reversed) });
        Ok(e.label)
@@ -407,11 +472,30 @@ impl Session {
                return Err(err);
            }
        };
+        self.show_undone(&e.op);
        self.pending_log.push(e.op);
        self.undo.push(UndoEntry { label: e.label.clone(), op: undo, folder: e.folder.as_ref().map(FolderMove::reversed) });
        Ok(e.label)
    }

+    /// After an undo or redo that changed one photo (its edit, rating, flag, label, metadata or
+    /// versions), that photo becomes the active one, as in Lightroom Classic, so the change is on
+    /// screen (issue #293). It joins the selection if it isn't in it; nothing changes for steps
+    /// that touch several photos, albums or files, or for a photo not in the current view.
+    fn show_undone(&mut self, op: &Op) {
+        let Some(id) = single_photo(op, 0) else { return };
+        if self.selection.active == Some(id) || !self.visible().contains(&id) {
+            return;
+        }
+        if !self.selection.contains(id) {
+            self.selection = Selection { ids: vec![id], active: Some(id) };
+        } else {
+            self.selection.active = Some(id);
+        }
+        self.active_mask = None;
+        self.active_spot = None;
+    }
+
    /// Apply an undo/redo op, first renaming the step's folder and moving the files its renames
    /// imply (all or nothing). Files that can't be moved back after a failure are reported and the
    /// library follows them (a logged change outside the undo history), so none goes missing; the
@@ -560,7 +644,12 @@ impl Session {

    /// Photos shown in the grid/filmstrip for the current source, filter and sort.
    pub fn visible(&mut self) -> &[PhotoId] {
-        let key = (self.catalog.revision, format!("{:?}|{:?}|{:?}|{:?}", self.source, self.filter, self.sort, self.browse));
+        let mut key =
+            (self.catalog.revision, format!("{:?}|{:?}|{:?}|{:?}|{:?}", self.source, self.filter, self.sort, self.browse, self.library_folder));
+        if self.source == LibrarySource::Missing && self.media.availability.is_background() {
+            // the view fills in as the background checks find files gone
+            key.1.push_str(&format!("|{}", self.media.availability.generation()));
+        }
        if self.visible_key.as_ref() != Some(&key) {
            // "in the last N days" rules count back from the session's clock
            lightcraft_catalog::rules::set_now(Some((self.clock)()));
@@ -571,7 +660,18 @@ impl Session {
                f.folder = Some(b.path);
                f.subfolders = b.subfolders;
            }
+            if self.source == LibrarySource::LibraryFolder {
+                // no folder chosen: nothing (`.` names no folder)
+                f.library_folder = Some(self.library_folder.clone().unwrap_or_else(|| ".".into()));
+            }
            let mut visible = self.catalog.query(&f, &self.sort);
+            if visible.is_empty() && self.source == LibrarySource::LibraryFolder && !self.folder_holds_photos() {
+                // the shown folder lost its last photo (deleted, moved, removed): everything, not
+                // an empty grid under the name of a folder that is gone from the sidebar
+                self.source = LibrarySource::All;
+                self.library_folder = None;
+                return self.visible();
+            }
            if matches!(self.source, LibrarySource::Album(_))
                && self.sort.key == lightcraft_catalog::SortKey::CaptureDate
                && let LibrarySource::Album(a) = self.source
@@ -595,8 +695,8 @@ impl Session {
            }
            if self.source == LibrarySource::Missing {
                // only the photos the query kept (library photos, not Local browse records) are checked
-                let cat = &self.catalog;
-                visible.retain(|id| cmd::missing::is_missing(cat, *id));
+                let (cat, avail) = (&self.catalog, &self.media.availability);
+                visible.retain(|id| cmd::missing::is_missing(cat, avail, *id));
            }
            if self.source != LibrarySource::RecentlyDeleted {
                visible = self.catalog.arrange_stacks(&visible);
@@ -608,13 +708,20 @@ impl Session {
        &self.visible
    }

+    /// Whether the library still holds a photo imported from the folder a `LibraryFolder` source
+    /// shows.
+    fn folder_holds_photos(&self) -> bool {
+        let f = Filter { library_folder: self.library_folder.clone(), ..Default::default() };
+        self.library_folder.is_some() && !self.catalog.query(&f, &Sort::default()).is_empty()
+    }
+
    /// Photos in the current source (folder, album, …) before the filter bar and search narrow
    /// them; `None` where that is not a separate number (Missing Photos).
    pub fn source_total(&mut self) -> Option<usize> {
        if self.source == LibrarySource::Missing {
            return None;
        }
-        let key = (self.catalog.revision, format!("{:?}|{:?}", self.source, self.browse));
+        let key = (self.catalog.revision, format!("{:?}|{:?}|{:?}", self.source, self.browse, self.library_folder));
        if self.total.as_ref().map(|t| &t.0) != Some(&key) {
            let mut f = self.source.to_filter(&Filter::default(), &self.catalog);
            if self.source == LibrarySource::Folder {
@@ -622,6 +729,9 @@ impl Session {
                f.folder = Some(b.path);
                f.subfolders = b.subfolders;
            }
+            if self.source == LibrarySource::LibraryFolder {
+                f.library_folder = Some(self.library_folder.clone().unwrap_or_else(|| ".".into()));
+            }
            let n = self.catalog.query(&f, &self.sort).len();
            self.total = Some((key, n));
        }
@@ -675,6 +785,8 @@ mod tests_color;
 #[cfg(test)]
 mod tests_export;
 #[cfg(test)]
+mod tests_folders;
+#[cfg(test)]
 mod tests_forget_local;
 #[cfg(test)]
 mod tests_import;
@@ -693,6 +805,8 @@ mod tests_persist;
 #[cfg(test)]
 mod tests_prefs;
 #[cfg(test)]
+mod tests_segment;
+#[cfg(test)]
 mod tests_settings_files;
 #[cfg(test)]
 mod tests_spots;
@@ -4,7 +4,7 @@
 //! ```text
 //! LightCraft Library/
 //!   catalog.snap   catalog.log      (lightcraft-catalog journal)
-//!   presets.json   view.json        (user presets + favourites; last source/filter/sort/selection)
+//!   presets.json   view.json        (user presets + favourites; last source/sort/selection)
 //!   prefs.json     (library preferences: XMP sidecars, import defaults, cache size, last export)
 //!   thumbs/        (rendered thumbnail cache, safe to delete)
 //!   Originals/     (photos imported with "copy into library")
@@ -102,7 +102,10 @@ struct PresetsFile {
 struct ViewFile {
    source: LibrarySource,
    browse: Option<crate::Browse>,
-    filter: lightcraft_catalog::Filter,
+    /// The folder a `libraryFolder` source shows.
+    library_folder: Option<String>,
+    // No filter: a library opens unfiltered. A date, keyword or person left over from the last session
+    // would silently hide photos, with only a small badge to say so.
    sort: lightcraft_catalog::Sort,
    selection: Selection,
 }
@@ -294,7 +297,13 @@ impl Session {
        {
            log::error!("library: {e}");
        }
-        let (mut journal, catalog, report) = Journal::open(catalog)?;
+        let (mut journal, mut catalog, report) = Journal::open(catalog)?;
+        // A loaded catalog counts revisions from 0, like every other one. Caches (sidebar counts,
+        // keyword tree, the grid's list…) are keyed on the revision, so give each library loaded
+        // in this process its own range: otherwise an empty library opened after one that was
+        // never edited this session would look unchanged and show the old library's numbers.
+        static LOADS: std::sync::atomic::AtomicU64 = std::sync::atomic::AtomicU64::new(0);
+        catalog.revision = LOADS.fetch_add(1, std::sync::atomic::Ordering::Relaxed).wrapping_add(1) << 32;
        self.catalog = catalog;
        self.undo.clear();
        self.redo.clear();
@@ -302,25 +311,12 @@ impl Session {
        self.pending_log.clear();
        self.selection = Selection::default();
        self.source = LibrarySource::All;
+        self.library_folder = None;
        if report.created && seed_demo {
            crate::demo::load(self);
            journal.snapshot(&self.catalog)?;
        }
        let mut settings = SettingsLoad::default();
-        // presets
-        if let Some(f) = settings.read::<PresetsFile>(files.as_mut(), "presets.json") {
-            for p in &mut self.presets {
-                p.favorite = p.builtin && f.favorites.contains(&p.id) || (!p.builtin && p.favorite);
-            }
-            for u in f.user {
-                if !self.presets.iter().any(|p| p.id == u.id) {
-                    self.presets.push(u);
-                }
-            }
-            let known = |id: &String| crate::presets::profile(id).is_some();
-            self.profile_favorites = f.profile_favorites.into_iter().filter(known).collect();
-            self.profile_recent = f.profile_recent.into_iter().filter(known).take(crate::presets::RECENT_PROFILES).collect();
-        }
        // preferences
        let prefs = settings.read::<PrefsFile>(files.as_mut(), "prefs.json").unwrap_or_default();
        self.xmp = prefs.xmp;
@@ -342,11 +338,34 @@ impl Session {
        if let Some(d) = &self.smart_previews_dir {
            self.media.smart_dir = Some(d.clone());
        }
+        // presets
+        if let Some(f) = settings.read::<PresetsFile>(files.as_mut(), "presets.json") {
+            for p in &mut self.presets {
+                p.favorite = p.builtin && f.favorites.contains(&p.id) || (!p.builtin && p.favorite);
+            }
+            for u in f.user {
+                if !self.presets.iter().any(|p| p.id == u.id) {
+                    self.presets.push(u);
+                }
+            }
+            let known = |id: &String| crate::presets::profile(id).is_some() || self.lut_profiles.iter().any(|p| &p.id == id);
+            self.profile_favorites = f.profile_favorites.into_iter().filter(known).collect();
+            self.profile_recent = f.profile_recent.into_iter().filter(known).take(crate::presets::RECENT_PROFILES).collect();
+        }
        // view state
        if let Some(v) = settings.read::<ViewFile>(files.as_mut(), "view.json") {
            self.source = v.source;
            self.browse = v.browse;
-            self.filter = v.filter;
+            self.library_folder = v.library_folder.filter(|f| !f.trim().is_empty());
+            if self.source == LibrarySource::LibraryFolder {
+                // a folder that is gone (or none): everything, not an empty grid
+                let f = lightcraft_catalog::Filter { library_folder: self.library_folder.clone(), ..Default::default() };
+                let any = self.library_folder.is_some() && !self.catalog.query(&f, &lightcraft_catalog::Sort::default()).is_empty();
+                if !any {
+                    self.source = LibrarySource::All;
+                    self.library_folder = None;
+                }
+            }
            self.sort = v.sort;
            self.selection = v.selection;
            self.selection.ids.retain(|id| self.catalog.photo(*id).is_some());
@@ -376,7 +395,7 @@ impl Session {
            forgot_local: None,
            presets_written,
            view_written,
-            settings_warnings: settings.warnings,
+            settings_warnings: unlocked_warning(lock.as_ref()).into_iter().chain(settings.warnings).collect(),
            warnings_reported: 0,
            blocked: settings.blocked,
            lock: lock.take(),
@@ -393,6 +412,7 @@ impl Session {
                lib.forgot_local = Some(plan);
            }
        }
+        self.library_identity = std::sync::Arc::new(());
        Ok(())
    }

@@ -485,26 +505,31 @@ impl Session {
            lib.retry_at = None;
            lib.last_error = None;
        }
-        match (persisted, snapshot) {
+        let result = match (persisted, snapshot) {
            (_, Ok(())) => Ok(()),
            // neither the log nor the snapshot took the queued ops
            (Err(EngineError::NotSaved(e)), Err(s)) if lib.journal.seq() == before => Err(EngineError::NotSaved(format!("{e}; snapshot: {s}"))),
            (_, Err(s)) => Err(s.into()),
+        };
+        if result.is_ok() {
+            self.library_identity = std::sync::Arc::new(());
        }
+        result
    }

    fn view_json(&self) -> Vec<u8> {
        let view = ViewFile {
            source: self.source,
            browse: self.browse.clone(),
-            filter: self.filter.clone(),
+            // only while it is shown: a leftover would be a stale choice nobody made
+            library_folder: self.library_folder.clone().filter(|_| self.source == LibrarySource::LibraryFolder),
            sort: self.sort,
            selection: self.selection.clone(),
        };
        serde_json::to_vec_pretty(&view).unwrap_or_default()
    }

-    /// Save the view state (source, filter, sort, selection) if it changed since it was last
+    /// Save the view state (source, sort, selection) if it changed since it was last
    /// written. Native hosts get this from [`Session::close_library`]; the browser host calls it
    /// periodically, since a tab can be closed without notice.
    pub fn save_view(&mut self) {
@@ -550,7 +575,8 @@ impl Session {
        lib.files.write_atomic("prefs.json", &v).map_err(|e| EngineError::Other(format!("prefs: {e}")))
    }

-    /// Settings-file warnings of the open library not handed out yet (the UI shows each once).
+    /// Warnings about the open library not handed out yet: its settings files, and a lock that
+    /// couldn't be taken (the UI shows each once; the CLI and MCP print them on stderr).
    pub fn take_library_warnings(&mut self) -> Vec<String> {
        let Some(lib) = self.library.as_mut() else { return vec![] };
        let new = lib.settings_warnings[lib.warnings_reported..].to_vec();
@@ -563,13 +589,14 @@ impl Session {
        if self.cache_mb == 0 { crate::media::DISK_CACHE_BYTES } else { u64::from(self.cache_mb) << 20 }
    }

-    /// Change the thumbnail disk cache budget (MB, 0 = default): re-attaches the cache, which
-    /// trims it to the new size. Saved with the library preferences.
+    /// Change the thumbnail disk cache budget (MB, 0 = default) in place: the cached thumbnails
+    /// stay (the next write trims to the new size), and so do the textures shown from them.
+    /// Saved with the library preferences.
    pub fn set_cache_mb(&mut self, mb: u32) -> Result<()> {
        self.cache_mb = mb;
        if let Some(lib) = self.library.as_ref().filter(|l| l.on_disk) {
            let dir = lib.thumbs_dir();
-            self.media.attach_disk_cache(&dir, self.cache_bytes());
+            self.media.set_disk_cache_bytes(&dir, self.cache_bytes());
        }
        self.save_prefs()
    }
@@ -604,3 +631,15 @@ impl Session {
        Ok(())
    }
 }
+
+/// The warning for a library opened without its one-program-at-a-time lock (issue #171): its
+/// file system can't lock `catalog.lock` (some network shares). It opens anyway, as documented —
+/// refusing would lock the user out — but the user must learn that a second program could open it.
+fn unlocked_warning(lock: Option<&LibraryLock>) -> Option<String> {
+    lock.filter(|l| !l.held()).map(|_| {
+        "This library could not be locked (its catalog.lock file can't be locked where it is stored, e.g. on some network \
+         shares), so it is open without protection against a second program: use it in one LightCraft app or command at \
+         a time, or changes made in one of them can be lost."
+            .to_string()
+    })
+}
@@ -0,0 +1,685 @@
+//! Bounded, deduplicated persistence for Lightroom import source data.
+//!
+//! Archives use a deterministic JSON representation wrapped in zlib.  The JSON
+//! writer streams through a bounded compressor, so an import cannot first build
+//! an unbounded archive buffer.  Blob columns are omitted by the catalog reader;
+//! decoded XMP,
+//! settings, history, snapshots, identities, paths, collections & membership
+//! remain available for recovery.
+
+use std::collections::BTreeMap;
+use std::fs::{self, File};
+use std::io::{self, Read, Write};
+use std::path::{Path, PathBuf};
+
+use miniz_oxide::deflate::{
+    core::{CompressorOxide, create_comp_flags_from_zip_params},
+    stream::deflate,
+};
+use miniz_oxide::{MZFlush, MZStatus};
+use serde::ser::{Serialize, SerializeMap, SerializeSeq, SerializeStruct, Serializer};
+use serde_json::Value;
+
+use crate::lightroom_catalog::{CatalogImport, CatalogPhoto};
+
+/// Maximum size of one complete archive on disk, including format header.
+pub const MAX_ARCHIVE_BYTES: u64 = 32 * 1024 * 1024;
+/// Maximum total size retained in managed archives.
+pub const MAX_TOTAL_ARCHIVE_BYTES: u64 = 128 * 1024 * 1024;
+/// Maximum number of managed archives retained.
+pub const MAX_MANAGED_ARCHIVES: usize = 8;
+
+const FORMAT_VERSION: u8 = 1;
+const HEADER: &[u8] = b"LC-LRARCH\0\x01Z";
+const NAME_PREFIX: &str = "lightroom-import-";
+const NAME_SUFFIX: &str = ".lca";
+const MAX_SCAN: usize = 1024;
+const IO_BUFFER: usize = 16 * 1024;
+
+/// Store compact source data below `directory` and return its managed archive.
+///
+/// The operation is safe to call before catalog mutation.  It rejects a
+/// symlink directory, writes only `lightroom-import-<number>.lca`, compares the
+/// complete bounded byte stream with recent managed archives, and retains at
+/// most [`MAX_MANAGED_ARCHIVES`] and [`MAX_TOTAL_ARCHIVE_BYTES`].  Legacy
+/// `lightroom-import-*.json` files are deliberately ignored and preserved for
+/// an explicit caller warning.
+pub fn store(directory: &Path, data: &CatalogImport) -> Result<PathBuf, String> {
+    prepare_directory(directory)?;
+    let mut managed = managed_files(directory)?;
+    managed.sort_by_key(|entry| entry.index);
+
+    let temporary = temporary_path(directory)?;
+    write_archive(&temporary, data).inspect_err(|_| {
+        let _ = remove_managed_file(&temporary);
+    })?;
+
+    let recent = managed.iter().rev().take(MAX_MANAGED_ARCHIVES);
+    for entry in recent {
+        let same = match same_bounded(&temporary, &entry.path) {
+            Ok(same) => same,
+            Err(error) => {
+                let _ = remove_managed_file(&temporary);
+                return Err(error.to_string());
+            }
+        };
+        if same {
+            remove_managed_file(&temporary).map_err(|e| e.to_string())?;
+            let matched = entry.path.clone();
+            let mut all = managed.clone();
+            prune_existing(directory, &mut all, Some(&matched))?;
+            return Ok(matched);
+        }
+    }
+
+    let index = managed.last().map_or(0, |entry| entry.index.saturating_add(1));
+    if managed.last().is_some_and(|entry| entry.index == u64::MAX) {
+        let _ = remove_managed_file(&temporary);
+        return Err("managed Lightroom archive index is exhausted".into());
+    }
+    let destination = match next_destination(directory, index) {
+        Ok(path) => path,
+        Err(error) => {
+            let _ = remove_managed_file(&temporary);
+            return Err(error);
+        }
+    };
+    let size = match fs::metadata(&temporary) {
+        Ok(meta) => meta.len(),
+        Err(error) => {
+            let _ = remove_managed_file(&temporary);
+            return Err(error.to_string());
+        }
+    };
+    let new_entry = Managed { index, path: destination.clone(), size };
+    let mut after = managed;
+    after.push(new_entry);
+    after.sort_by_key(|entry| entry.index);
+    let retirees = match retirement_set(&after) {
+        Ok(retirees) => retirees,
+        Err(error) => {
+            let _ = remove_managed_file(&temporary);
+            return Err(error);
+        }
+    };
+    let quarantined = match quarantine(&retirees) {
+        Ok(quarantined) => quarantined,
+        Err(error) => {
+            let _ = remove_managed_file(&temporary);
+            return Err(error);
+        }
+    };
+
+    if let Err(error) = publish_new(&temporary, &destination) {
+        rollback_quarantine(&quarantined);
+        let _ = remove_managed_file(&temporary);
+        return Err(error.to_string());
+    }
+    if let Err(error) = remove_managed_file(&temporary) {
+        return Err(format!("archive published but temporary cleanup failed: {error}"));
+    }
+    for (old, held) in quarantined {
+        if let Err(error) = remove_managed_file(&held) {
+            return Err(format!("archive published but could not retire {}: {error}", old.display()));
+        }
+    }
+    Ok(destination)
+}
+
+/// Store source data when possible. An archive that reaches its bounded size is
+/// omitted with a warning so catalog import can still complete.
+pub fn store_best_effort(directory: &Path, data: &CatalogImport) -> Result<Option<PathBuf>, String> {
+    match store(directory, data) {
+        Ok(path) => Ok(Some(path)),
+        Err(error) if error.contains("Lightroom archive exceeds 32 MiB") => Ok(None),
+        Err(error) => Err(error),
+    }
+}
+
+#[derive(Clone, Debug)]
+struct Managed {
+    index: u64,
+    path: PathBuf,
+    size: u64,
+}
+
+fn prepare_directory(directory: &Path) -> Result<(), String> {
+    match fs::symlink_metadata(directory) {
+        Ok(meta) => {
+            if meta.file_type().is_symlink() || !meta.is_dir() {
+                return Err(format!("archive directory is not a real directory: {}", directory.display()));
+            }
+        }
+        Err(error) if error.kind() == io::ErrorKind::NotFound => {
+            fs::create_dir_all(directory).map_err(|e| e.to_string())?;
+            let meta = fs::symlink_metadata(directory).map_err(|e| e.to_string())?;
+            if meta.file_type().is_symlink() || !meta.is_dir() {
+                return Err(format!("archive directory is not a real directory: {}", directory.display()));
+            }
+        }
+        Err(error) => return Err(error.to_string()),
+    }
+    Ok(())
+}
+
+fn managed_files(directory: &Path) -> Result<Vec<Managed>, String> {
+    let mut files = Vec::new();
+    for (seen, result) in fs::read_dir(directory).map_err(|e| e.to_string())?.enumerate() {
+        if seen >= MAX_SCAN {
+            return Err(format!("too many entries in archive directory (limit {MAX_SCAN})"));
+        }
+        let entry = result.map_err(|e| e.to_string())?;
+        let Some(index) = parse_managed_name(&entry.file_name()) else { continue };
+        let meta = fs::symlink_metadata(entry.path()).map_err(|e| e.to_string())?;
+        if meta.file_type().is_symlink() || !meta.is_file() {
+            continue;
+        }
+        files.push(Managed { index, path: entry.path(), size: meta.len() });
+    }
+    Ok(files)
+}
+
+fn parse_managed_name(name: &std::ffi::OsStr) -> Option<u64> {
+    let name = name.to_str()?;
+    let digits = name.strip_prefix(NAME_PREFIX)?.strip_suffix(NAME_SUFFIX)?;
+    if digits.is_empty() || !digits.bytes().all(|byte| byte.is_ascii_digit()) {
+        return None;
+    }
+    digits.parse().ok()
+}
+
+fn temporary_path(directory: &Path) -> Result<PathBuf, String> {
+    let pid = std::process::id();
+    for slot in 0..MAX_SCAN {
+        let path = directory.join(format!(".lightroom-import-{pid}-{slot}.tmp"));
+        match fs::symlink_metadata(&path) {
+            Ok(_) => continue,
+            Err(error) if error.kind() == io::ErrorKind::NotFound => return Ok(path),
+            Err(error) => return Err(error.to_string()),
+        }
+    }
+    Err("no safe temporary archive name available".into())
+}
+
+fn next_destination(directory: &Path, mut index: u64) -> Result<PathBuf, String> {
+    for _ in 0..MAX_SCAN {
+        let path = directory.join(format!("{NAME_PREFIX}{index}{NAME_SUFFIX}"));
+        match fs::symlink_metadata(&path) {
+            Ok(_) => index = index.checked_add(1).ok_or("managed archive index is exhausted")?,
+            Err(error) if error.kind() == io::ErrorKind::NotFound => return Ok(path),
+            Err(error) => return Err(error.to_string()),
+        }
+    }
+    Err("no safe managed archive name available".into())
+}
+
+fn write_archive(path: &Path, data: &CatalogImport) -> Result<(), String> {
+    lightcraft_catalog::safe_file::write_atomic_with(path, &mut |raw| {
+        let mut bounded = BoundedWriter { inner: raw, total: 0 };
+        bounded.write_all(HEADER)?;
+        let mut compressor = ZlibWriter::new(&mut bounded);
+        serde_json::to_writer(&mut compressor, &ArchiveRef(data)).map_err(json_io)?;
+        compressor.finish()?;
+        Ok(())
+    })
+    .map(|_| ())
+    .map_err(|error| format!("could not write Lightroom archive: {error}"))
+}
+
+fn json_io(error: serde_json::Error) -> io::Error {
+    io::Error::new(io::ErrorKind::InvalidData, error.to_string())
+}
+
+struct BoundedWriter<'a> {
+    inner: &'a mut dyn Write,
+    total: u64,
+}
+
+impl Write for BoundedWriter<'_> {
+    fn write(&mut self, bytes: &[u8]) -> io::Result<usize> {
+        let next = self.total.checked_add(bytes.len() as u64).ok_or_else(limit_error)?;
+        if next > MAX_ARCHIVE_BYTES {
+            return Err(limit_error());
+        }
+        self.inner.write_all(bytes)?;
+        self.total = next;
+        Ok(bytes.len())
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        self.inner.flush()
+    }
+}
+
+fn limit_error() -> io::Error {
+    io::Error::new(io::ErrorKind::InvalidData, "Lightroom archive exceeds 32 MiB")
+}
+
+struct ZlibWriter<'a, 'b> {
+    sink: &'a mut BoundedWriter<'b>,
+    compressor: CompressorOxide,
+    plain: u64,
+}
+
+impl<'a, 'b> ZlibWriter<'a, 'b> {
+    fn new(sink: &'a mut BoundedWriter<'b>) -> ZlibWriter<'a, 'b> {
+        let flags = create_comp_flags_from_zip_params(6, 15, 0);
+        ZlibWriter { sink, compressor: CompressorOxide::new(flags), plain: 0 }
+    }
+
+    fn run(&mut self, input: &[u8], flush: MZFlush) -> io::Result<()> {
+        let mut rest = input;
+        loop {
+            let mut output = [0u8; IO_BUFFER];
+            let result = deflate(&mut self.compressor, rest, &mut output, flush);
+            self.sink.write_all(&output[..result.bytes_written])?;
+            match result.status {
+                Ok(MZStatus::StreamEnd) => return Ok(()),
+                Ok(MZStatus::Ok) => {
+                    let consumed = result.bytes_consumed;
+                    if consumed > rest.len() {
+                        return Err(io::Error::new(io::ErrorKind::InvalidData, "invalid compressor progress"));
+                    }
+                    rest = &rest[consumed..];
+                    if rest.is_empty() && flush == MZFlush::None {
+                        return Ok(());
+                    }
+                    if consumed == 0 && result.bytes_written == 0 {
+                        return Err(io::Error::new(io::ErrorKind::InvalidData, "compressor made no progress"));
+                    }
+                }
+                Ok(status) => {
+                    return Err(io::Error::new(io::ErrorKind::InvalidData, format!("unsupported compressor status: {status:?}")));
+                }
+                Err(error) => return Err(io::Error::new(io::ErrorKind::InvalidData, format!("compression failed: {error:?}"))),
+            }
+        }
+    }
+
+    fn finish(&mut self) -> io::Result<()> {
+        self.run(&[], MZFlush::Finish)
+    }
+}
+
+impl Write for ZlibWriter<'_, '_> {
+    fn write(&mut self, bytes: &[u8]) -> io::Result<usize> {
+        if bytes.is_empty() {
+            return Ok(0);
+        }
+        let next = self.plain.checked_add(bytes.len() as u64).ok_or_else(limit_error)?;
+        if next > MAX_ARCHIVE_BYTES {
+            return Err(limit_error());
+        }
+        self.run(bytes, MZFlush::None)?;
+        self.plain = next;
+        Ok(bytes.len())
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        Ok(())
+    }
+}
+
+fn same_bounded(left: &Path, right: &Path) -> io::Result<bool> {
+    let left_meta = fs::symlink_metadata(left)?;
+    let right_meta = fs::symlink_metadata(right)?;
+    if left_meta.file_type().is_symlink() || right_meta.file_type().is_symlink() || !left_meta.is_file() || !right_meta.is_file() {
+        return Ok(false);
+    }
+    let left_len = left_meta.len();
+    let right_len = right_meta.len();
+    if left_len != right_len || left_len > MAX_ARCHIVE_BYTES {
+        return Ok(false);
+    }
+    let mut left = File::open(left)?;
+    let mut right = File::open(right)?;
+    let mut left_buf = [0u8; IO_BUFFER];
+    let mut right_buf = [0u8; IO_BUFFER];
+    loop {
+        let left_n = left.read(&mut left_buf)?;
+        let right_n = right.read(&mut right_buf)?;
+        if left_n != right_n {
+            return Ok(false);
+        }
+        if left_n == 0 {
+            return Ok(true);
+        }
+        if left_buf[..left_n] != right_buf[..right_n] {
+            return Ok(false);
+        }
+    }
+}
+
+fn retirement_set(entries: &[Managed]) -> Result<Vec<Managed>, String> {
+    retirement_set_protected(entries, None)
+}
+
+fn retirement_set_protected(entries: &[Managed], protected: Option<&Path>) -> Result<Vec<Managed>, String> {
+    let mut ordered = entries.to_vec();
+    ordered.sort_by_key(|entry| entry.index);
+    let mut total = ordered.iter().try_fold(0u64, |sum, entry| sum.checked_add(entry.size)).ok_or("archive size overflow")?;
+    let mut retirees = Vec::new();
+    while ordered.len() > MAX_MANAGED_ARCHIVES || total > MAX_TOTAL_ARCHIVE_BYTES {
+        let Some(position) = ordered.iter().position(|entry| protected.is_none_or(|path| entry.path != path)) else {
+            return Err("cannot satisfy archive retention limit".into());
+        };
+        let oldest = ordered.remove(position);
+        total = total.saturating_sub(oldest.size);
+        retirees.push(oldest);
+    }
+    Ok(retirees)
+}
+
+fn prune_existing(directory: &Path, entries: &mut [Managed], protected: Option<&Path>) -> Result<(), String> {
+    let retirees = retirement_set_protected(entries, protected)?;
+    let quarantined = quarantine(&retirees)?;
+    for (old, held) in quarantined {
+        if let Err(error) = remove_managed_file(&held) {
+            return Err(format!("could not retire {} from {}: {error}", old.display(), directory.display()));
+        }
+    }
+    Ok(())
+}
+
+fn quarantine(entries: &[Managed]) -> Result<Vec<(PathBuf, PathBuf)>, String> {
+    let mut moved = Vec::new();
+    let pid = std::process::id();
+    for (slot, entry) in entries.iter().enumerate() {
+        let held = entry.path.with_file_name(format!(".lightroom-retire-{pid}-{slot}.tmp"));
+        match fs::symlink_metadata(&held) {
+            Ok(_) => {
+                rollback_quarantine(&moved);
+                return Err(format!("retention temporary path already exists: {}", held.display()));
+            }
+            Err(error) if error.kind() == io::ErrorKind::NotFound => {}
+            Err(error) => {
+                rollback_quarantine(&moved);
+                return Err(error.to_string());
+            }
+        }
+        let meta = fs::symlink_metadata(&entry.path).map_err(|error| {
+            rollback_quarantine(&moved);
+            error.to_string()
+        })?;
+        if meta.file_type().is_symlink() || !meta.is_file() {
+            rollback_quarantine(&moved);
+            return Err(format!("managed archive changed into non-file: {}", entry.path.display()));
+        }
+        if let Err(error) = fs::rename(&entry.path, &held) {
+            rollback_quarantine(&moved);
+            return Err(error.to_string());
+        }
+        moved.push((entry.path.clone(), held));
+    }
+    Ok(moved)
+}
+
+fn rollback_quarantine(moved: &[(PathBuf, PathBuf)]) {
+    for (original, held) in moved.iter().rev() {
+        let _ = fs::rename(held, original);
+    }
+}
+
+fn publish_new(temporary: &Path, destination: &Path) -> io::Result<()> {
+    match fs::hard_link(temporary, destination) {
+        Ok(()) => Ok(()),
+        Err(error) => Err(io::Error::new(error.kind(), format!("cannot atomically publish archive: {error}"))),
+    }
+}
+
+fn remove_managed_file(path: &Path) -> io::Result<()> {
+    let meta = fs::symlink_metadata(path)?;
+    if meta.file_type().is_symlink() || !meta.is_file() {
+        return Err(io::Error::new(io::ErrorKind::InvalidInput, "refusing to remove non-regular archive path"));
+    }
+    fs::remove_file(path)
+}
+
+struct ArchiveRef<'a>(&'a CatalogImport);
+
+impl Serialize for ArchiveRef<'_> {
+    fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
+        let mut out = serializer.serialize_struct("CatalogImportArchive", 7)?;
+        out.serialize_field("version", &FORMAT_VERSION)?;
+        out.serialize_field("source", &self.0.source)?;
+        out.serialize_field("photos", &PhotoSeq(&self.0.photos))?;
+        out.serialize_field("collections", &RowSeq(&self.0.collections))?;
+        out.serialize_field("members", &RowSeq(&self.0.members))?;
+        out.serialize_field("collection_content", &RowSeq(&self.0.collection_content))?;
+        out.serialize_field("warnings", &self.0.warnings)?;
+        out.end()
+    }
+}
+
+struct PhotoSeq<'a>(&'a [CatalogPhoto]);
+impl Serialize for PhotoSeq<'_> {
+    fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
+        let mut out = serializer.serialize_seq(Some(self.0.len()))?;
+        for photo in self.0 {
+            out.serialize_element(&PhotoRef(photo))?;
+        }
+        out.end()
+    }
+}
+
+struct PhotoRef<'a>(&'a CatalogPhoto);
+impl Serialize for PhotoRef<'_> {
+    fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
+        let p = self.0;
+        let mut out = serializer.serialize_struct("CatalogPhotoArchive", 8)?;
+        out.serialize_field("source_id", &p.source_id)?;
+        out.serialize_field("uuid", &p.uuid)?;
+        out.serialize_field("path", &p.path)?;
+        out.serialize_field("image", &RowRef(&p.image))?;
+        out.serialize_field("settings", &p.settings)?;
+        out.serialize_field("xmp", &p.xmp)?;
+        out.serialize_field("keywords", &p.keywords)?;
+        out.serialize_field("history", &RowSeq(&p.history))?;
+        out.serialize_field("snapshots", &RowSeq(&p.snapshots))?;
+        out.end()
+    }
+}
+
+struct RowSeq<'a>(&'a [BTreeMap<String, Value>]);
+impl Serialize for RowSeq<'_> {
+    fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
+        let mut out = serializer.serialize_seq(Some(self.0.len()))?;
+        for row in self.0 {
+            out.serialize_element(&RowRef(row))?;
+        }
+        out.end()
+    }
+}
+
+struct RowRef<'a>(&'a BTreeMap<String, Value>);
+impl Serialize for RowRef<'_> {
+    fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
+        let mut out = serializer.serialize_map(None)?;
+        for (key, value) in self.0 {
+            out.serialize_entry(key, value)?;
+        }
+        out.end()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::lightroom_catalog::{CatalogImport, CatalogPhoto};
+    use std::sync::atomic::{AtomicU64, Ordering};
+
+    static NEXT: AtomicU64 = AtomicU64::new(0);
+
+    fn tempdir() -> PathBuf {
+        let path = std::env::temp_dir().join(format!("lightcraft-lr-archive-{}-{}", std::process::id(), NEXT.fetch_add(1, Ordering::Relaxed)));
+        fs::create_dir_all(&path).unwrap();
+        path
+    }
+
+    fn data(source: String) -> CatalogImport {
+        CatalogImport {
+            source,
+            photos: Vec::new(),
+            collections: Vec::new(),
+            members: Vec::new(),
+            collection_content: Vec::new(),
+            warnings: Vec::new(),
+        }
+    }
+
+    fn rich_data() -> CatalogImport {
+        let photo = CatalogPhoto {
+            source_id: 7,
+            uuid: "uuid-7".into(),
+            path: "/photos/one.raw".into(),
+            image: BTreeMap::from([("rating".into(), serde_json::json!(5)), ("opaque_blob".into(), serde_json::json!([1, 2, 3, 4]))]),
+            settings: "s = { Exposure2012 = 0.75 }".into(),
+            xmp: "<xmp>decoded</xmp>".into(),
+            keywords: vec!["Trips|Goa".into()],
+            history: vec![BTreeMap::from([("text".into(), serde_json::json!("step")), ("curve".into(), serde_json::json!([0, 128, 255]))])],
+            snapshots: vec![BTreeMap::from([("name".into(), serde_json::json!("before"))])],
+        };
+        CatalogImport {
+            source: "source.lrcat".into(),
+            photos: vec![photo],
+            collections: vec![BTreeMap::from([("name".into(), serde_json::json!("Keepers"))])],
+            members: vec![BTreeMap::from([("image".into(), serde_json::json!(7))])],
+            collection_content: vec![BTreeMap::from([("rule".into(), serde_json::json!("rating > 3"))])],
+            warnings: vec!["one warning".into()],
+        }
+    }
+
+    fn managed_count(path: &Path) -> usize {
+        fs::read_dir(path).unwrap().filter_map(Result::ok).filter(|entry| parse_managed_name(&entry.file_name()).is_some()).count()
+    }
+
+    #[test]
+    fn deduplicates_identical_deterministic_archives() {
+        let path = tempdir();
+        let input = data("catalog.lrcat".into());
+        let first = store(&path, &input).unwrap();
+        let second = store(&path, &input).unwrap();
+        assert_eq!(first, second);
+        assert_eq!(managed_count(&path), 1);
+        fs::remove_dir_all(path).unwrap();
+    }
+
+    #[test]
+    fn dedup_returns_archive_that_retention_keeps() {
+        let path = tempdir();
+        let input = data("catalog.lrcat".into());
+        let first = store(&path, &input).unwrap();
+        for index in 1..MAX_MANAGED_ARCHIVES {
+            let filler = path.join(format!("lightroom-import-{index}.lca"));
+            File::create(filler).unwrap().set_len(19 * 1024 * 1024).unwrap();
+        }
+        let reused = store(&path, &input).unwrap();
+        assert_eq!(reused, first);
+        assert!(reused.is_file());
+        assert!(managed_count(&path) <= MAX_MANAGED_ARCHIVES);
+        fs::remove_dir_all(path).unwrap();
+    }
+
+    #[test]
+    fn caps_managed_archive_count_and_preserves_unrelated_files() {
+        let path = tempdir();
+        let human = path.join("notes.txt");
+        let legacy = path.join("lightroom-import-0.json");
+        fs::write(&human, b"keep").unwrap();
+        fs::write(&legacy, b"legacy").unwrap();
+        for index in 0..(MAX_MANAGED_ARCHIVES + 3) {
+            let input = data(format!("catalog-{index}.lrcat"));
+            store(&path, &input).unwrap();
+        }
+        assert!(managed_count(&path) <= MAX_MANAGED_ARCHIVES);
+        assert_eq!(fs::read(&human).unwrap(), b"keep");
+        assert_eq!(fs::read(&legacy).unwrap(), b"legacy");
+        fs::remove_dir_all(path).unwrap();
+    }
+
+    #[test]
+    fn rejects_oversize_before_creating_archive() {
+        let path = tempdir();
+        let input = data("x".repeat((MAX_ARCHIVE_BYTES as usize) + 1));
+        assert!(store(&path, &input).is_err());
+        assert_eq!(managed_count(&path), 0);
+        fs::remove_dir_all(path).unwrap();
+    }
+
+    #[test]
+    fn large_catalog_history_is_best_effort_and_does_not_abort_import() {
+        let path = tempdir();
+        let mut input = data("catalog.lrcat".into());
+        input.photos = (0..5_000)
+            .map(|index| CatalogPhoto {
+                source_id: index,
+                uuid: format!("photo-{index}"),
+                path: format!("/photos/{index}.raw"),
+                image: BTreeMap::new(),
+                settings: String::new(),
+                xmp: String::new(),
+                keywords: Vec::new(),
+                history: vec![BTreeMap::from([("text".into(), serde_json::json!(format!("history-{index}-{}", "x".repeat(8 * 1024))))])],
+                snapshots: Vec::new(),
+            })
+            .collect();
+        assert_eq!(store_best_effort(&path, &input).unwrap(), None);
+        assert_eq!(managed_count(&path), 0);
+        fs::remove_dir_all(path).unwrap();
+    }
+
+    #[test]
+    fn archive_roundtrips_zlib_payload_and_preserves_numeric_arrays() {
+        let path = tempdir();
+        let archive = store(&path, &rich_data()).unwrap();
+        let bytes = fs::read(archive).unwrap();
+        assert!(bytes.starts_with(HEADER));
+        let json = miniz_oxide::inflate::decompress_to_vec_zlib_with_limit(&bytes[HEADER.len()..], MAX_ARCHIVE_BYTES as usize).unwrap();
+        let decoded: Value = serde_json::from_slice(&json).unwrap();
+        assert_eq!(decoded["version"], serde_json::json!(FORMAT_VERSION));
+        assert_eq!(decoded["source"], serde_json::json!("source.lrcat"));
+        assert_eq!(decoded["photos"].as_array().unwrap().len(), 1);
+        assert_eq!(decoded["photos"][0]["source_id"], serde_json::json!(7));
+        assert_eq!(decoded["photos"][0]["uuid"], serde_json::json!("uuid-7"));
+        assert_eq!(decoded["photos"][0]["path"], serde_json::json!("/photos/one.raw"));
+        assert_eq!(decoded["photos"][0]["settings"], serde_json::json!("s = { Exposure2012 = 0.75 }"));
+        assert_eq!(decoded["photos"][0]["xmp"], serde_json::json!("<xmp>decoded</xmp>"));
+        assert_eq!(decoded["photos"][0]["keywords"], serde_json::json!(["Trips|Goa"]));
+        assert_eq!(decoded["photos"][0]["image"]["rating"], serde_json::json!(5));
+        assert_eq!(decoded["photos"][0]["image"]["opaque_blob"], serde_json::json!([1, 2, 3, 4]));
+        assert_eq!(decoded["photos"][0]["history"].as_array().unwrap().len(), 1);
+        assert_eq!(decoded["photos"][0]["history"][0]["curve"], serde_json::json!([0, 128, 255]));
+        assert_eq!(decoded["photos"][0]["snapshots"].as_array().unwrap().len(), 1);
+        assert_eq!(decoded["collections"].as_array().unwrap().len(), 1);
+        assert_eq!(decoded["collections"][0]["name"], serde_json::json!("Keepers"));
+        assert_eq!(decoded["members"].as_array().unwrap().len(), 1);
+        assert_eq!(decoded["members"][0]["image"], serde_json::json!(7));
+        assert_eq!(decoded["collection_content"].as_array().unwrap().len(), 1);
+        assert_eq!(decoded["warnings"], serde_json::json!(["one warning"]));
+        fs::remove_dir_all(path).unwrap();
+    }
+
+    #[test]
+    fn retention_enforces_aggregate_byte_cap_with_small_synthetic_entries() {
+        let mut entries: Vec<_> = (0..MAX_MANAGED_ARCHIVES as u64)
+            .map(|index| Managed { index, path: PathBuf::from(format!("lightroom-import-{index}.lca")), size: 20 * 1024 * 1024 })
+            .collect();
+        entries.push(Managed { index: 8, path: PathBuf::from("lightroom-import-8.lca"), size: 20 * 1024 * 1024 });
+        let retirees = retirement_set(&entries).unwrap();
+        assert_eq!(retirees.len(), 3);
+        assert_eq!(retirees.iter().map(|entry| entry.index).collect::<Vec<_>>(), vec![0, 1, 2]);
+    }
+
+    #[test]
+    fn retention_failure_preserves_old_archive() {
+        let path = tempdir();
+        let old = path.join("lightroom-import-0.lca");
+        let held = path.join(format!(".lightroom-retire-{}-0.tmp", std::process::id()));
+        fs::write(&old, b"old archive").unwrap();
+        fs::write(&held, b"occupied").unwrap();
+        let entry = Managed { index: 0, path: old.clone(), size: 11 };
+        assert!(quarantine(&[entry]).is_err());
+        assert_eq!(fs::read(&old).unwrap(), b"old archive");
+        fs::remove_dir_all(path).unwrap();
+    }
+}
@@ -0,0 +1,450 @@
+//! Detached Lightroom catalog preparation and owner-thread commit.
+//!
+//! `LightroomJob::new` takes only an in-memory session snapshot.  `prepare` owns all catalog
+//! reading, probing and archive staging, while `commit_prepared` only applies catalog operations
+//! to the session that created the job.  Archive index bytes are returned for a worker to finish
+//! after the owner has accepted the catalog operation.
+
+use std::collections::HashSet;
+use std::path::{Path, PathBuf};
+use std::sync::{
+    Arc,
+    atomic::{AtomicBool, AtomicUsize, Ordering},
+};
+
+use serde_json::Value;
+
+use crate::import::{ImportJob, ImportMode, ImportOptions, Prepared};
+use crate::lightroom_catalog::{self, CatalogImport, ImportIndex};
+
+const COMMAND: &str = "library.importLightroom";
+const MAX_INDEX_BYTES: usize = 16 * 1024 * 1024;
+
+fn error(message: impl Into<String>) -> crate::EngineError {
+    crate::EngineError::BadParams { cmd: COMMAND.into(), msg: message.into() }
+}
+
+fn stage_archive(archive_dir: Option<&Path>, data: &mut CatalogImport) -> crate::Result<Option<PathBuf>> {
+    let archive_path = archive_dir.map(|dir| crate::lightroom_archive::store_best_effort(dir, data).map_err(error)).transpose()?.flatten();
+    if archive_dir.is_some() && archive_path.is_none() {
+        data.warnings.push("Lightroom source archive exceeded 32 MiB; archive skipped".into());
+    }
+    Ok(archive_path)
+}
+
+/// Memory identity of the library which owns a prepared completion.
+///
+/// Each successful open/close refreshes session identity, including reopening the same path.
+/// The owner check deliberately does not compare catalog revisions: ordinary edits while preparation
+/// runs must survive and are merged by the owner commit.
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub struct LightroomLibraryToken {
+    library_dir: Option<PathBuf>,
+    identity: Arc<()>,
+}
+
+impl LightroomLibraryToken {
+    fn capture(s: &crate::Session) -> Self {
+        Self {
+            library_dir: s.library.as_ref().filter(|library| library.on_disk).map(|library| library.dir.clone()),
+            identity: Arc::clone(&s.library_identity),
+        }
+    }
+
+    /// Whether `s` still refers to the library which started preparation.
+    pub fn matches(&self, s: &crate::Session) -> bool {
+        Arc::ptr_eq(&self.identity, &s.library_identity)
+            && self.library_dir == s.library.as_ref().filter(|library| library.on_disk).map(|library| library.dir.clone())
+    }
+
+    pub fn library_dir(&self) -> Option<&Path> {
+        self.library_dir.as_deref()
+    }
+}
+
+/// Filesystem-free result of catalog preparation.
+pub struct PreparedLightroom {
+    pub(crate) data: CatalogImport,
+    pub(crate) normal: Prepared,
+    pub(crate) index: ImportIndex,
+    pub(crate) archive_path: Option<PathBuf>,
+    pub(crate) token: LightroomLibraryToken,
+    pub(crate) missing_sources: HashSet<String>,
+    pub(crate) update_existing: bool,
+    pub(crate) now: String,
+    cancelled: bool,
+}
+
+impl PreparedLightroom {
+    pub fn source(&self) -> &str {
+        &self.data.source
+    }
+
+    pub fn photo_count(&self) -> usize {
+        self.data.photos.len()
+    }
+
+    pub fn token(&self) -> &LightroomLibraryToken {
+        &self.token
+    }
+
+    pub fn is_cancelled(&self) -> bool {
+        self.cancelled
+    }
+
+    /// Roll back any normal-import filesystem placement held by this prepared value.
+    pub fn rollback(&self) {
+        self.normal.rollback();
+    }
+}
+
+/// Index write returned by owner commit.  `finish` is intended for a worker after the owner has
+/// returned, and performs the only archive-index filesystem operation in this pipeline.
+pub struct LightroomArchiveFinalization {
+    path: Option<PathBuf>,
+    bytes: Option<Vec<u8>>,
+}
+
+impl LightroomArchiveFinalization {
+    pub fn finish(self) -> crate::Result<()> {
+        let (Some(path), Some(bytes)) = (self.path, self.bytes) else { return Ok(()) };
+        if bytes.len() > MAX_INDEX_BYTES {
+            return Err(error("Lightroom import index exceeds 16 MiB"));
+        }
+        lightcraft_catalog::safe_file::write_atomic(&path, &bytes).map_err(|e| error(e.to_string()))
+    }
+
+    pub fn path(&self) -> Option<&Path> {
+        self.path.as_deref()
+    }
+}
+
+/// Owner-thread catalog result.  The report is ready for the UI immediately; index finalization
+/// can remain on the worker while its task stays alive.
+pub struct LightroomCompletion {
+    pub report: Value,
+    pub finalization: LightroomArchiveFinalization,
+}
+
+/// Alias used by hosts that call the result a commit.
+pub type LightroomCommit = LightroomCompletion;
+
+/// A Lightroom import detached from the owner thread.
+pub struct LightroomJob {
+    path: PathBuf,
+    update_existing: bool,
+    import: ImportJob,
+    token: LightroomLibraryToken,
+    archive_dir: Option<PathBuf>,
+}
+
+impl LightroomJob {
+    /// Snapshot session state only.  This constructor performs no filesystem work.
+    pub fn new(s: &mut crate::Session, path: PathBuf, update_existing: bool) -> crate::Result<Self> {
+        let opts = ImportOptions { mode: ImportMode::Add, ..ImportOptions::default() };
+        let import = ImportJob::new(s, opts)?;
+        let archive_dir = s.library.as_ref().filter(|library| library.on_disk).map(|library| library.dir.join("Interop"));
+        Ok(Self { path, update_existing, import, token: LightroomLibraryToken::capture(s), archive_dir })
+    }
+
+    pub fn total(&self) -> usize {
+        self.import.total.load(Ordering::Relaxed)
+    }
+
+    pub fn done(&self) -> usize {
+        self.import.done.load(Ordering::Relaxed)
+    }
+
+    pub fn progress(&self) -> (usize, usize) {
+        (self.done(), self.total())
+    }
+
+    pub fn token(&self) -> &LightroomLibraryToken {
+        &self.token
+    }
+
+    pub fn total_atomic(&self) -> std::sync::Arc<AtomicUsize> {
+        std::sync::Arc::clone(&self.import.total)
+    }
+
+    pub fn done_atomic(&self) -> std::sync::Arc<AtomicUsize> {
+        std::sync::Arc::clone(&self.import.done)
+    }
+
+    /// Finish an owner commit's deferred archive-index write on a worker.
+    pub fn finish_archive(finalization: LightroomArchiveFinalization) -> crate::Result<()> {
+        finalization.finish()
+    }
+
+    /// Read/probe/stage all source data off the owner thread.
+    pub fn prepare(&mut self, cancel: &AtomicBool) -> crate::Result<PreparedLightroom> {
+        if cancel.load(Ordering::Relaxed) {
+            return Err(error("Lightroom import cancelled"));
+        }
+        self.import.total.store(1, Ordering::Relaxed);
+        self.import.done.store(0, Ordering::Relaxed);
+        let mut data = lightroom_catalog::read_with_progress(&self.path, cancel, &self.import.total, &self.import.done).map_err(error)?;
+        lightroom_catalog::validate_for_job(&data).map_err(error)?;
+        if cancel.load(Ordering::Relaxed) {
+            return Err(error("Lightroom import cancelled"));
+        }
+        self.import.done.fetch_add(1, Ordering::Relaxed);
+        let paths: Vec<String> = data
+            .photos
+            .iter()
+            .filter(|photo| lightroom_catalog::number_for_job(&photo.image, "masterImage") == 0)
+            .map(|photo| photo.path.clone())
+            .collect();
+        let missing_sources = data
+            .photos
+            .iter()
+            .filter(|photo| lightroom_catalog::number_for_job(&photo.image, "masterImage") == 0)
+            .filter(|photo| !Path::new(&photo.path).is_file())
+            .map(|photo| normalize(&photo.path))
+            .collect();
+        let normal = self.import.prepare(&paths, cancel);
+        if cancel.load(Ordering::Relaxed) {
+            normal.rollback();
+            return Err(error("Lightroom import cancelled"));
+        }
+        let archive_path = stage_archive(self.archive_dir.as_deref(), &mut data)?;
+        let index_path = self.archive_dir.as_ref().map(|dir| dir.join("lightroom-index.json"));
+        let index = lightroom_catalog::load_index(index_path.as_deref())?;
+        Ok(PreparedLightroom {
+            data,
+            normal,
+            index,
+            archive_path,
+            token: self.token.clone(),
+            missing_sources,
+            update_existing: self.update_existing,
+            now: self.import.now().to_string(),
+            cancelled: cancel.load(Ordering::Relaxed),
+        })
+    }
+}
+
+/// Apply prepared data on the owner thread.  No source, archive or index filesystem work occurs.
+pub fn commit_prepared(s: &mut crate::Session, mut prepared: PreparedLightroom) -> crate::Result<LightroomCompletion> {
+    if prepared.cancelled {
+        prepared.normal.rollback();
+        return Err(error("Lightroom import cancelled"));
+    }
+    if !prepared.token.matches(s) {
+        prepared.normal.rollback();
+        return Err(error("Lightroom import belongs to a different open library"));
+    }
+    // A command-scoped Lightroom import must never rewrite source XMP sidecars.  Direct depth-0
+    // callers do not set this transient flag, so they cannot affect a later command.
+    if s.depth > 0 {
+        s.skip_auto_write = true;
+    }
+
+    let undo0 = s.undo.len();
+    prepared.normal.revalidate_add(s);
+    let options = ImportOptions { mode: ImportMode::Add, ..ImportOptions::default() };
+    let now = prepared.now.clone();
+    let files = crate::import::commit_prepared(s, &options, &now, prepared.normal)?;
+    let applied = lightroom_catalog::apply_prepared(
+        s,
+        prepared.data,
+        lightroom_catalog::ApplyPrepared {
+            update_existing: prepared.update_existing,
+            files,
+            index: &mut prepared.index,
+            archive_path: prepared.archive_path,
+            missing_sources: &prepared.missing_sources,
+            undo0,
+        },
+    )?;
+    let path = prepared.token.library_dir().map(|dir| dir.join("Interop/lightroom-index.json"));
+    let bytes = if path.is_some() { Some(serde_json::to_vec(&applied.index).map_err(|e| error(e.to_string()))?) } else { None };
+    Ok(LightroomCompletion { report: applied.report, finalization: LightroomArchiveFinalization { path, bytes } })
+}
+
+fn normalize(path: &str) -> String {
+    let path = path.replace('\\', "/");
+    if cfg!(windows) { path.to_lowercase() } else { path }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn empty_data() -> CatalogImport {
+        CatalogImport {
+            source: "fixture.lrcat".into(),
+            photos: Vec::new(),
+            collections: Vec::new(),
+            members: Vec::new(),
+            collection_content: Vec::new(),
+            warnings: Vec::new(),
+        }
+    }
+
+    fn cancelled_prepared(s: &crate::Session) -> PreparedLightroom {
+        PreparedLightroom {
+            data: empty_data(),
+            normal: Prepared::default(),
+            index: ImportIndex::default(),
+            archive_path: None,
+            token: LightroomLibraryToken::capture(s),
+            missing_sources: HashSet::new(),
+            update_existing: false,
+            now: "2026-01-01T00:00:00".into(),
+            cancelled: true,
+        }
+    }
+
+    fn prepared_for(s: &crate::Session, path: &str, rating: i64) -> PreparedLightroom {
+        let mut image = std::collections::BTreeMap::new();
+        image.insert("id_local".into(), serde_json::json!(1));
+        image.insert("rating".into(), serde_json::json!(rating));
+        image.insert("pick".into(), serde_json::json!(0));
+        image.insert("fileFormat".into(), serde_json::json!("JPG"));
+        image.insert("fileWidth".into(), serde_json::json!(1));
+        image.insert("fileHeight".into(), serde_json::json!(1));
+        PreparedLightroom {
+            data: CatalogImport {
+                source: "fixture.lrcat".into(),
+                photos: vec![lightroom_catalog::CatalogPhoto {
+                    source_id: 1,
+                    uuid: "fixture-photo".into(),
+                    path: path.into(),
+                    image,
+                    settings: String::new(),
+                    xmp: String::new(),
+                    keywords: Vec::new(),
+                    history: Vec::new(),
+                    snapshots: Vec::new(),
+                }],
+                collections: Vec::new(),
+                members: Vec::new(),
+                collection_content: Vec::new(),
+                warnings: Vec::new(),
+            },
+            normal: Prepared::default(),
+            index: ImportIndex::default(),
+            archive_path: None,
+            token: LightroomLibraryToken::capture(s),
+            missing_sources: [normalize(path)].into_iter().collect(),
+            update_existing: false,
+            now: "2026-01-01T00:00:00".into(),
+            cancelled: false,
+        }
+    }
+
+    #[test]
+    fn cancellation_before_commit_leaves_owner_catalog_unchanged() {
+        let mut session = crate::Session::new();
+        let before = session.catalog.to_snapshot();
+        let prepared = cancelled_prepared(&session);
+        assert!(commit_prepared(&mut session, prepared).is_err());
+        assert_eq!(session.catalog.to_snapshot(), before);
+        assert!(session.undo.is_empty());
+    }
+
+    #[test]
+    fn library_identity_rejects_late_completion_after_reopen() {
+        let mut session = crate::Session::new();
+        let token = LightroomLibraryToken::capture(&session);
+        assert!(token.matches(&session));
+        session.library_identity = Arc::new(());
+        assert!(!token.matches(&session));
+    }
+
+    #[test]
+    fn prepared_reimport_preserves_current_edit_and_uses_one_undo_per_import() {
+        let mut session = crate::Session::new();
+        let path = "/missing/lightroom-job-edit.jpg";
+        let prepared = prepared_for(&session, path, 4);
+        let first = commit_prepared(&mut session, prepared).unwrap();
+        assert_eq!(first.report["mapping"]["1"].as_u64(), Some(1));
+        assert_eq!(session.undo.len(), 1);
+        let id = lightcraft_catalog::PhotoId(1);
+        let mut personal = lightcraft_develop::DevelopSettings::default();
+        personal.light.exposure = 1.5;
+        session.set_develop(id, personal, "Personal").unwrap();
+        let before = session.catalog.photo(id).map(|photo| photo.develop.clone());
+        let prepared = prepared_for(&session, path, 5);
+        commit_prepared(&mut session, prepared).unwrap();
+        assert_eq!(session.catalog.photo(id).map(|photo| photo.develop.clone()), before);
+        assert_eq!(session.catalog.photo(id).map(|photo| photo.rating), Some(5));
+        assert_eq!(session.undo.len(), 3);
+    }
+
+    #[test]
+    fn oversized_history_archive_keeps_prepared_import_successful_with_warning() {
+        let archive_dir = std::env::temp_dir().join(format!("lightcraft-lr-prepared-scale-{}", std::process::id()));
+        let mut data = empty_data();
+        data.photos = (0..5_000)
+            .map(|source_id| {
+                let image = std::collections::BTreeMap::from([
+                    ("id_local".into(), serde_json::json!(source_id)),
+                    ("fileFormat".into(), serde_json::json!("JPG")),
+                    ("fileWidth".into(), serde_json::json!(1)),
+                    ("fileHeight".into(), serde_json::json!(1)),
+                ]);
+                lightroom_catalog::CatalogPhoto {
+                    source_id,
+                    uuid: format!("scale-{source_id}"),
+                    path: format!("/missing/scale-{source_id}.jpg"),
+                    image,
+                    settings: String::new(),
+                    xmp: String::new(),
+                    keywords: Vec::new(),
+                    history: vec![std::collections::BTreeMap::from([(
+                        "text".into(),
+                        serde_json::json!(format!("history-{source_id}-{}", "x".repeat(8 * 1024))),
+                    )])],
+                    snapshots: Vec::new(),
+                }
+            })
+            .collect();
+        let archive_path = stage_archive(Some(&archive_dir), &mut data).unwrap();
+        assert!(archive_path.is_none());
+        let mut session = crate::Session::new();
+        let token = LightroomLibraryToken::capture(&session);
+        let prepared = PreparedLightroom {
+            data,
+            normal: Prepared::default(),
+            index: ImportIndex::default(),
+            archive_path,
+            token,
+            missing_sources: HashSet::new(),
+            update_existing: false,
+            now: "2026-01-01T00:00:00".into(),
+            cancelled: false,
+        };
+        let completion = commit_prepared(&mut session, prepared).unwrap();
+        assert_eq!(completion.report["photos"], 5_000);
+        assert!(
+            completion.report["warnings"]
+                .as_array()
+                .is_some_and(|warnings| warnings.iter().any(|warning| warning == "Lightroom source archive exceeded 32 MiB; archive skipped"))
+        );
+        assert_eq!(session.catalog.len(), 5_000);
+        std::fs::remove_dir_all(archive_dir).unwrap();
+    }
+
+    #[test]
+    fn execute_fn_import_does_not_rewrite_source_sidecar() {
+        let dir = std::env::temp_dir().join(format!("lightcraft-lr-job-sidecar-{}", std::process::id()));
+        let path = dir.join("source.jpg");
+        let sidecar = dir.join("source.xmp");
+        std::fs::create_dir_all(&dir).unwrap();
+        std::fs::write(&path, b"fixture").unwrap();
+        std::fs::write(&sidecar, b"original sidecar").unwrap();
+        let original = std::fs::read(&sidecar).unwrap();
+        let mut session = crate::Session::new();
+        session.xmp.auto_write = true;
+        let result = session.execute_fn("library.importLightroom", |s| {
+            let prepared = prepared_for(s, &path.to_string_lossy(), 5);
+            let completion = commit_prepared(s, prepared)?;
+            Ok(completion.report)
+        });
+        assert!(result.is_ok());
+        assert_eq!(std::fs::read(&sidecar).unwrap(), original);
+        std::fs::remove_dir_all(dir).unwrap();
+    }
+}
@@ -0,0 +1,118 @@
+//! `log` records on stderr for the native desktop app and CLI (#168). The web build installs
+//! eframe's `WebLogger` instead.
+//!
+//! Warnings and errors are shown by default. `LIGHTCRAFT_LOG` or `RUST_LOG` picks another level
+//! (`off`, `error`, `warn`, `info`, `debug`, `trace`); `LIGHTCRAFT_LOG` wins when both are set.
+//! `RUST_LOG` also accepts per-target directives (`lightcraft=debug,wgpu=warn`): a bare level
+//! applies to everything, and the most verbose `lightcraft…=level` directive sets LightCraft's.
+//! Below warnings only LightCraft's own records are shown, so `info` and `debug` aren't drowned
+//! out by the GPU and windowing libraries.
+
+use log::{Level, LevelFilter, Metadata, Record};
+
+/// Records shown at a level, written to stderr as `<prefix>: LEVEL target: message`.
+pub struct StderrLog {
+    prefix: &'static str,
+    level: LevelFilter,
+}
+
+impl StderrLog {
+    pub fn new(prefix: &'static str, level: LevelFilter) -> Self {
+        Self { prefix, level }
+    }
+}
+
+impl log::Log for StderrLog {
+    fn enabled(&self, m: &Metadata) -> bool {
+        m.level() <= self.level && (m.level() <= Level::Warn || m.target().starts_with("lightcraft"))
+    }
+    fn log(&self, r: &Record) {
+        if self.enabled(r.metadata()) {
+            eprintln!("{}: {} {}: {}", self.prefix, r.level(), r.target(), r.args());
+        }
+    }
+    fn flush(&self) {}
+}
+
+fn parse_level(s: &str) -> Option<LevelFilter> {
+    match s.trim().to_ascii_lowercase().as_str() {
+        "off" | "none" => Some(LevelFilter::Off),
+        "error" => Some(LevelFilter::Error),
+        "warn" | "warning" => Some(LevelFilter::Warn),
+        "info" => Some(LevelFilter::Info),
+        "debug" => Some(LevelFilter::Debug),
+        "trace" => Some(LevelFilter::Trace),
+        _ => None,
+    }
+}
+
+/// The level that `LIGHTCRAFT_LOG` / `RUST_LOG` ask for; warnings when neither names one.
+pub fn level_from(lightcraft_log: Option<&str>, rust_log: Option<&str>) -> LevelFilter {
+    if let Some(l) = lightcraft_log.and_then(parse_level) {
+        return l;
+    }
+    let Some(rust_log) = rust_log else { return LevelFilter::Warn };
+    let mut bare = None;
+    let mut ours: Option<LevelFilter> = None;
+    for directive in rust_log.split(',') {
+        match directive.split_once('=') {
+            None => bare = parse_level(directive).or(bare),
+            Some((target, level)) if target.trim().starts_with("lightcraft") => {
+                if let Some(l) = parse_level(level) {
+                    ours = Some(ours.map_or(l, |o| o.max(l)));
+                }
+            }
+            Some(_) => {}
+        }
+    }
+    ours.or(bare).unwrap_or(LevelFilter::Warn)
+}
+
+/// Install the stderr logger at the level the environment asks for. Does nothing when a logger is
+/// already installed.
+pub fn install(prefix: &'static str) {
+    let level = level_from(std::env::var("LIGHTCRAFT_LOG").ok().as_deref(), std::env::var("RUST_LOG").ok().as_deref());
+    static LOGGER: std::sync::OnceLock<StderrLog> = std::sync::OnceLock::new();
+    if log::set_logger(LOGGER.get_or_init(|| StderrLog::new(prefix, level))).is_ok() {
+        log::set_max_level(level);
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use log::Log;
+
+    #[test]
+    fn warnings_by_default_and_either_variable_picks_the_level() {
+        assert_eq!(level_from(None, None), LevelFilter::Warn);
+        assert_eq!(level_from(None, Some("")), LevelFilter::Warn);
+        assert_eq!(level_from(None, Some("warn")), LevelFilter::Warn);
+        assert_eq!(level_from(None, Some("TRACE")), LevelFilter::Trace);
+        assert_eq!(level_from(None, Some("off")), LevelFilter::Off);
+        assert_eq!(level_from(Some("info"), None), LevelFilter::Info);
+        assert_eq!(level_from(Some("error"), Some("debug")), LevelFilter::Error, "LIGHTCRAFT_LOG wins");
+        assert_eq!(level_from(Some("nonsense"), Some("debug")), LevelFilter::Debug, "an unknown LIGHTCRAFT_LOG is ignored");
+    }
+
+    #[test]
+    fn rust_log_directives_set_lightcraft_s_level() {
+        assert_eq!(level_from(None, Some("lightcraft=debug,wgpu=warn")), LevelFilter::Debug);
+        assert_eq!(level_from(None, Some("wgpu_core=trace")), LevelFilter::Warn, "other crates' directives don't apply");
+        assert_eq!(level_from(None, Some("error,lightcraft_gpu=info")), LevelFilter::Info);
+        assert_eq!(level_from(None, Some("lightcraft_gpu=info,lightcraft_engine=trace")), LevelFilter::Trace);
+        assert_eq!(level_from(None, Some("info,naga=off")), LevelFilter::Info);
+    }
+
+    #[test]
+    fn only_lightcraft_records_below_warnings() {
+        let log = StderrLog::new("test", LevelFilter::Debug);
+        let meta = |level, target| Metadata::builder().level(level).target(target).build();
+        assert!(log.enabled(&meta(Level::Warn, "wgpu_core::device")));
+        assert!(log.enabled(&meta(Level::Debug, "lightcraft_gpu::ctx")));
+        assert!(!log.enabled(&meta(Level::Info, "wgpu_core::device")));
+        assert!(!log.enabled(&meta(Level::Trace, "lightcraft_gpu::ctx")));
+        let quiet = StderrLog::new("test", LevelFilter::Off);
+        assert!(!quiet.enabled(&meta(Level::Error, "lightcraft_engine")));
+    }
+}
@@ -16,7 +16,8 @@
 //! embedded JPEG for an unedited raw, else a thumbnail-level render — while the real render is
 //! prepared. Grid thumbnails of unedited raws likewise start from the embedded preview.

-use std::sync::Arc;
+use std::collections::{HashMap, VecDeque};
+use std::sync::{Arc, Weak};

 use lightcraft_catalog::{MediaKind, Photo, PhotoId, Source};
 use lightcraft_develop::DevelopSettings;
@@ -25,12 +26,51 @@ use lightcraft_preview::{Hash128, Hasher128, Lru, PreviewCache};
 use lightcraft_raster::{Histogram, Rgb32f, Rgba8};
 use serde::{Deserialize, Serialize};

+const SETTINGS_HASH_ENTRIES: usize = 1024;
+
+#[derive(Default)]
+struct SettingsHashes {
+    entries: HashMap<PhotoId, (Weak<DevelopSettings>, u64)>,
+    order: VecDeque<PhotoId>,
+    #[cfg(test)]
+    computations: usize,
+}
+
+impl SettingsHashes {
+    fn get(&mut self, id: PhotoId, settings: &Arc<DevelopSettings>) -> u64 {
+        if let Some((old, hash)) = self.entries.get(&id)
+            && old.as_ptr() == Arc::as_ptr(settings)
+        {
+            return *hash;
+        }
+        let hash = settings.hash64();
+        #[cfg(test)]
+        {
+            self.computations += 1;
+        }
+        if !self.entries.contains_key(&id) {
+            if self.entries.len() >= SETTINGS_HASH_ENTRIES
+                && let Some(oldest) = self.order.pop_front()
+            {
+                self.entries.remove(&oldest);
+            }
+            self.order.push_back(id);
+        }
+        self.entries.insert(id, (Arc::downgrade(settings), hash));
+        hash
+    }
+}
+
 /// Bump when the pipeline's output changes, to invalidate cached thumbnails.
-pub const RENDER_CACHE_VERSION: u64 = 4;
+pub const RENDER_CACHE_VERSION: u64 = 14;

 /// Thumbnails render at one of these long edges (so window/cell size changes reuse the cache).
 pub const THUMB_SIZES: [usize; 4] = [128, 256, 384, 512];

+pub fn thumb_bucket(long_edge: usize) -> usize {
+    THUMB_SIZES.iter().copied().find(|s| *s >= long_edge).unwrap_or(512)
+}
+
 /// Memory budgets.
 const THUMB_SOURCE_BYTES: usize = 384 << 20;
 const RENDERED_MEM_BYTES: usize = 128 << 20;
@@ -71,9 +111,31 @@ pub type FileLoader = Arc<dyn Fn(&str, usize) -> Result<(Rgb32f, SourceInfo), St
 /// `max_edge` (set by the app). `None`: no usable preview.
 pub type PreviewLoader = Arc<dyn Fn(&str, usize) -> Option<Rgba8> + Send + Sync>;

+/// Pixels and the source interpretation learned while decoding; they must be cached together.
+#[derive(Clone)]
+pub struct DecodedSource {
+    pub image: Arc<Rgb32f>,
+    pub info: Option<SourceInfo>,
+    /// A smart preview's stored camera tone curve: the one decoder fact its pixels need that the
+    /// catalog's header facts lack (used when `info` is `None`).
+    pub camera_tone: Option<lightcraft_pipeline::tone::CameraTone>,
+}
+
+impl DecodedSource {
+    pub fn new(image: Arc<Rgb32f>, info: Option<SourceInfo>) -> Self {
+        DecodedSource { image, info, camera_tone: None }
+    }
+
+    /// What to render these pixels against: the decoder's facts, else `header` (the catalog's)
+    /// with any stored camera tone curve.
+    pub fn info_or(&self, header: SourceInfo) -> SourceInfo {
+        self.info.unwrap_or(SourceInfo { camera_tone: self.camera_tone.or(header.camera_tone), ..header })
+    }
+}
+
 #[derive(Clone)]
 pub enum SourceRef {
-    Loaded(Arc<Rgb32f>),
+    Loaded(Box<DecodedSource>),
    Demo {
        scene: Box<lightcraft_scenes::Scene>,
        max_edge: usize,
@@ -82,6 +144,9 @@ pub enum SourceRef {
        path: String,
        max_edge: usize,
        loader: Option<FileLoader>,
+        /// The photo's smart preview, used when the original can't be read (offline drive). The
+        /// UI thread never checks whether the original is there; the render worker finds out.
+        fallback: Option<std::path::PathBuf>,
    },
    /// A smart preview standing in for a missing original.
    Smart {
@@ -91,28 +156,42 @@ pub enum SourceRef {

 impl SourceRef {
    pub fn load(&self) -> Result<Arc<Rgb32f>, String> {
-        match self {
-            SourceRef::Loaded(a) => Ok(a.clone()),
-            SourceRef::Demo { scene, max_edge } => Ok(Arc::new(scene.render_fit(*max_edge))),
-            SourceRef::File { path, max_edge, loader } => match loader {
-                Some(l) => l(path, *max_edge).map(|(img, _)| Arc::new(img)),
-                None => Err(format!("no decoder available for {path}")),
-            },
+        self.load_source().map(|s| s.image)
+    }
+
+    pub fn load_source(&self) -> Result<DecodedSource, String> {
+        let image = match self {
+            SourceRef::Loaded(a) => return Ok((**a).clone()),
+            SourceRef::Demo { scene, max_edge } => Arc::new(scene.render_fit(*max_edge)),
+            SourceRef::File { path, max_edge, loader, fallback } => {
+                let r = match loader {
+                    Some(l) => l(path, *max_edge).map(|(image, info)| DecodedSource::new(Arc::new(image), Some(info))),
+                    None => Err(format!("no decoder available for {path}")),
+                };
+                // An offline original renders from its smart preview (no decoder facts: header ones).
+                return match (r, fallback) {
+                    #[cfg(not(target_arch = "wasm32"))]
+                    (Err(e), Some(sp)) if crate::smart::is_valid(sp) => crate::smart::load(sp).map_err(|e2| format!("{e}; smart preview: {e2}")),
+                    (r, _) => r,
+                };
+            }
            #[cfg(not(target_arch = "wasm32"))]
-            SourceRef::Smart { path } => crate::smart::load(path),
+            SourceRef::Smart { path } => return crate::smart::load(path),
            #[cfg(target_arch = "wasm32")]
-            SourceRef::Smart { .. } => Err("smart previews are not available here".into()),
-        }
+            SourceRef::Smart { .. } => return Err("smart previews are not available here".into()),
+        };
+        Ok(DecodedSource::new(image, None))
    }
 }

 pub struct MediaCache {
+    settings_hashes: SettingsHashes,
    /// Decoded thumbnail-level sources (LRU by bytes).
-    thumbs: Lru<PhotoId, Arc<Rgb32f>>,
+    thumbs: Lru<PhotoId, DecodedSource>,
    /// Decoded preview-level sources with their last use ([`lightcraft_preview::next_tick`]).
-    previews: Vec<(PhotoId, Arc<Rgb32f>, u64)>,
+    previews: Vec<(PhotoId, DecodedSource, u64)>,
    /// The last full-resolution original (exports; one at a time: ~300 MB at 24 MP).
-    full: Option<(PhotoId, Arc<Rgb32f>, u64)>,
+    full: Option<(PhotoId, DecodedSource, u64)>,
    /// How many previews to keep (LRU).
    pub preview_capacity: usize,
    /// Bytes all decoded sources and rendered previews in memory may take together (the cache
@@ -125,6 +204,9 @@ pub struct MediaCache {
    pub file_bytes: Option<crate::merge::ByteReader>,
    /// The library's smart previews folder (originals offline: render from the proxy).
    pub smart_dir: Option<std::path::PathBuf>,
+    /// Whether originals (and smart previews) are on disk: cached and checked off the UI thread
+    /// in the app (see [`crate::availability`]).
+    pub availability: crate::availability::Availability,
    scenes: Vec<lightcraft_scenes::Scene>,
    /// Rendered thumbnails (memory, plus disk once a library is attached).
    pub rendered: Arc<PreviewCache>,
@@ -134,6 +216,7 @@ impl Default for MediaCache {
    fn default() -> Self {
        let budget = crate::memory::cache_share(crate::memory::budget());
        MediaCache {
+            settings_hashes: SettingsHashes::default(),
            thumbs: Lru::new(THUMB_SOURCE_BYTES.min(budget)),
            previews: Vec::new(),
            full: None,
@@ -144,6 +227,7 @@ impl Default for MediaCache {
            preview_loader: None,
            file_bytes: None,
            smart_dir: None,
+            availability: Default::default(),
            scenes: Vec::new(),
            rendered: Arc::new(PreviewCache::memory(rendered_budget(budget))),
        }
@@ -156,17 +240,31 @@ fn rendered_budget(share: usize) -> usize {
 }

 fn source_bytes(img: &Rgb32f) -> usize {
-    img.data.len() * 12 + 64
+    img.data.len() * 12 + 64 + std::mem::size_of::<SourceInfo>()
 }

 impl MediaCache {
-    /// Keep rendered thumbnails on disk in `dir` as well.
+    /// Keep rendered thumbnails on disk in `dir` as well. The cache this replaces is retired
+    /// (its files stay): render jobs still holding it can't write through it any more, even
+    /// into a directory a later clear emptied (`dir` may be the same one).
    pub fn attach_disk_cache(&mut self, dir: &std::path::Path, disk_bytes: u64) {
+        self.rendered.retire();
        self.rendered = Arc::new(PreviewCache::with_disk(rendered_budget(self.budget), dir, disk_bytes));
    }

+    /// Change the disk budget of the cache in `dir`: in place when that cache is attached (its
+    /// thumbnails are keyed by content, so they and the textures shown from them stay valid,
+    /// and the same cache object keeps its generation), else attach it.
+    pub fn set_disk_cache_bytes(&mut self, dir: &std::path::Path, disk_bytes: u64) {
+        match self.rendered.disk().filter(|d| d.dir() == dir) {
+            Some(d) => d.set_budget(disk_bytes),
+            None => self.attach_disk_cache(dir, disk_bytes),
+        }
+    }
+
    /// Forget every decoded source (photo ids changed meaning, e.g. another library was opened).
    pub fn clear_sources(&mut self) {
+        self.settings_hashes = SettingsHashes::default();
        self.thumbs = Lru::new(THUMB_SOURCE_BYTES.min(self.budget));
        self.previews.clear();
        self.full = None;
@@ -207,8 +305,8 @@ impl MediaCache {
            let Some((tick, which)) = candidates.into_iter().flatten().min() else { break };
            let freed = match which {
                0 => self.thumbs.pop_oldest(),
-                1 => self.previews.iter().position(|e| e.2 == tick).map(|i| source_bytes(&self.previews.remove(i).1)),
-                2 => self.full.take().map(|e| source_bytes(&e.1)),
+                1 => self.previews.iter().position(|e| e.2 == tick).map(|i| source_bytes(&self.previews.remove(i).1.image)),
+                2 => self.full.take().map(|e| source_bytes(&e.1.image)),
                _ => self.rendered.evict_oldest(),
            };
            match freed {
@@ -219,6 +317,10 @@ impl MediaCache {
    }

    pub fn get(&mut self, id: PhotoId, level: SourceLevel) -> Option<Arc<Rgb32f>> {
+        self.get_source(id, level).map(|s| s.image)
+    }
+
+    fn get_source(&mut self, id: PhotoId, level: SourceLevel) -> Option<DecodedSource> {
        match level {
            SourceLevel::Thumb => self.thumbs.get(&id).cloned(),
            SourceLevel::Preview => self.previews.iter_mut().find(|e| e.0 == id).map(|e| {
@@ -232,11 +334,31 @@ impl MediaCache {
        }
    }

+    /// The facts of photo `id`'s cached sources: the decoder's when one has them, else `header`
+    /// (with a smart preview's stored camera tone curve).
+    fn source_facts(&self, id: PhotoId, header: SourceInfo) -> SourceInfo {
+        let cached = || {
+            self.thumbs
+                .peek(&id)
+                .into_iter()
+                .chain(self.previews.iter().filter(|e| e.0 == id).map(|e| &e.1))
+                .chain(self.full.iter().filter(|e| e.0 == id).map(|e| &e.1))
+        };
+        match cached().find(|s| s.info.is_some()).or_else(|| cached().next()) {
+            Some(s) => s.info_or(header),
+            None => header,
+        }
+    }
+
    pub fn insert(&mut self, id: PhotoId, level: SourceLevel, img: Arc<Rgb32f>) {
+        self.insert_source(id, level, DecodedSource::new(img, None));
+    }
+
+    fn insert_source(&mut self, id: PhotoId, level: SourceLevel, img: DecodedSource) {
        let tick = lightcraft_preview::next_tick();
        match level {
            SourceLevel::Thumb => {
-                let cost = source_bytes(&img);
+                let cost = source_bytes(&img.image);
                self.thumbs.insert(id, img, cost);
            }
            SourceLevel::Preview => {
@@ -270,29 +392,36 @@ impl MediaCache {
    /// Decoded sources held: (thumbnail level, preview level, full size).
    pub fn usage(&self) -> (crate::memory::Usage, crate::memory::Usage, crate::memory::Usage) {
        use crate::memory::Usage;
-        let previews = Usage::new(self.previews.len(), self.previews.iter().map(|e| source_bytes(&e.1)).sum());
-        let full = self.full.as_ref().map(|e| Usage::new(1, source_bytes(&e.1))).unwrap_or_default();
+        let previews = Usage::new(self.previews.len(), self.previews.iter().map(|e| source_bytes(&e.1.image)).sum());
+        let full = self.full.as_ref().map(|e| Usage::new(1, source_bytes(&e.1.image))).unwrap_or_default();
        (Usage::new(self.thumbs.len(), self.thumbs.cost()), previews, full)
    }

    pub fn source_ref(&mut self, p: &Photo, level: SourceLevel) -> SourceRef {
-        if let Some(a) = self.get(p.id, level) {
-            return SourceRef::Loaded(a);
+        if let Some(a) = self.get_source(p.id, level) {
+            return SourceRef::Loaded(Box::new(a));
        }
        // Procedural scenes have a nominal size: "full" is that size, not unbounded.
        let max_edge = level.max_edge().min(match (&p.source, level) {
            (Source::Demo { .. }, SourceLevel::Full) => p.width.max(p.height).max(1) as usize,
            _ => usize::MAX,
        });
-        // the original is offline: its smart preview, when there is one
+        // the original is offline: its smart preview, when there is one. Only cached answers are
+        // used here (no file-system call on the UI thread in the app); an original not known to
+        // be offline is tried first and its smart preview is the render worker's fallback.
        #[cfg(not(target_arch = "wasm32"))]
-        if let (Source::File { path }, Some(dir)) = (&p.source, &self.smart_dir)
-            && !std::path::Path::new(path).exists()
-        {
+        if let (Source::File { path }, Some(dir)) = (&p.source, &self.smart_dir) {
            let sp = dir.join(crate::smart::file_name(p));
-            if crate::smart::is_valid(&sp) {
+            // (a proxy cut short fails to load, like the offline original; the worker's fallback
+            // in `SourceRef::load` only uses a proxy that passes `smart::is_valid`)
+            if self.availability.is_offline(path) && self.availability.exists(&sp.to_string_lossy()) == Some(true) {
                return SourceRef::Smart { path: sp };
            }
+            let mut r = self.origin_ref(&p.source, max_edge);
+            if let SourceRef::File { fallback, .. } = &mut r {
+                *fallback = Some(sp);
+            }
+            return r;
        }
        self.origin_ref(&p.source, max_edge)
    }
@@ -307,10 +436,10 @@ impl MediaCache {
                }
                match self.scenes.iter().find(|s| s.id == *scene) {
                    Some(s) => SourceRef::Demo { scene: Box::new(s.clone()), max_edge },
-                    None => SourceRef::File { path: format!("demo:{scene}"), max_edge, loader: None },
+                    None => SourceRef::File { path: format!("demo:{scene}"), max_edge, loader: None, fallback: None },
                }
            }
-            Source::File { path } => SourceRef::File { path: path.clone(), max_edge, loader: self.file_loader.clone() },
+            Source::File { path } => SourceRef::File { path: path.clone(), max_edge, loader: self.file_loader.clone(), fallback: None },
        }
    }
 }
@@ -318,6 +447,11 @@ impl MediaCache {
 /// Everything needed to render one photo, detached from the session.
 #[derive(Clone)]
 pub struct RenderJob {
+    /// Assigned by a frontend to distinguish late completions, even for an identical render key.
+    pub request_id: u64,
+    pub cache_generation: u64,
+    /// Content identity for validating a decoded source returned after a reload.
+    pub source_key: Option<Hash128>,
    pub photo: PhotoId,
    pub level: SourceLevel,
    pub source: SourceRef,
@@ -339,12 +473,14 @@ pub struct RenderJob {
 }

 pub struct RenderResult {
+    pub request_id: u64,
+    pub source_key: Option<Hash128>,
    pub photo: PhotoId,
    pub level: SourceLevel,
    pub key: u64,
    pub rendered: Result<Rendered, String>,
    /// A source that was loaded by this job (to be inserted into the cache).
-    pub loaded: Option<Arc<Rgb32f>>,
+    pub loaded: Option<DecodedSource>,
    /// Set for a [`QuickJob`]'s stand-in: where the image came from.
    pub quick: Option<QuickSource>,
 }
@@ -396,11 +532,13 @@ impl RenderJob {

    pub fn run(self) -> RenderResult {
        if let Some((cache, key)) = &self.cache
-            && let Some(img) = cache.get(*key)
+            && let Some(img) = cache.get_at(self.cache_generation, *key)
        {
            let image = Arc::unwrap_or_clone(img);
            let histogram = Histogram::of_srgb8(&image);
            return RenderResult {
+                request_id: self.request_id,
+                source_key: self.source_key,
                photo: self.photo,
                level: self.level,
                key: self.key,
@@ -410,30 +548,43 @@ impl RenderJob {
            };
        }
        let was_loaded = matches!(self.source, SourceRef::Loaded(_));
-        match self.source.load() {
-            Ok(src) => {
+        match self.source.load_source() {
+            Ok(source) => {
+                let src = &source.image;
+                let info = source.info_or(self.info);
                // Thumbnails (many small jobs side by side) stay on the CPU; views and exports use
                // the GPU when there is one.
                let gpu = self.cache.is_none();
-                let rendered = develop(&src, &self.info, &self.settings, &self.request, self.stages.as_deref(), gpu);
+                let rendered = develop(src, &info, &self.settings, &self.request, self.stages.as_deref(), gpu);
                if let Some((cache, key)) = &self.cache {
-                    cache.put(*key, Arc::new(rendered.image.clone()));
+                    cache.put_at(self.cache_generation, *key, Arc::new(rendered.image.clone()));
                }
                if let Some((cache, key)) = &self.view_cache
                    && self.request.quality == Quality::Full
                {
-                    cache.put_deferred(*key, Arc::new(rendered.image.clone()));
+                    cache.put_deferred_at(self.cache_generation, *key, Arc::new(rendered.image.clone()));
                }
                RenderResult {
+                    request_id: self.request_id,
+                    source_key: self.source_key,
                    photo: self.photo,
                    level: self.level,
                    key: self.key,
                    rendered: Ok(rendered),
-                    loaded: (!was_loaded).then_some(src),
+                    loaded: (!was_loaded).then_some(source),
                    quick: None,
                }
            }
-            Err(e) => RenderResult { photo: self.photo, level: self.level, key: self.key, rendered: Err(e), loaded: None, quick: None },
+            Err(e) => RenderResult {
+                request_id: self.request_id,
+                source_key: self.source_key,
+                photo: self.photo,
+                level: self.level,
+                key: self.key,
+                rendered: Err(e),
+                loaded: None,
+                quick: None,
+            },
        }
    }
 }
@@ -473,6 +624,7 @@ pub enum QuickSource {
 /// renders, the embedded preview of an unedited raw, a thumbnail-level render.
 #[derive(Clone)]
 pub struct QuickJob {
+    pub request_id: u64,
    pub photo: PhotoId,
    pub key: u64,
    /// Cached renders to try first, in order: (cache, key).
@@ -486,7 +638,17 @@ pub struct QuickJob {
 impl QuickJob {
    pub fn run(self) -> RenderResult {
        let (photo, key) = (self.photo, self.key);
-        let done = |rendered: Result<Rendered, String>, quick| RenderResult { photo, level: SourceLevel::Thumb, key, rendered, loaded: None, quick };
+        let request_id = self.request_id;
+        let done = |rendered: Result<Rendered, String>, quick| RenderResult {
+            request_id,
+            source_key: None,
+            photo,
+            level: SourceLevel::Thumb,
+            key,
+            rendered,
+            loaded: None,
+            quick,
+        };
        let rendered = |image: Rgba8| {
            let histogram = Histogram::of_srgb8(&image);
            Ok(Rendered { image, histogram, deep: None })
@@ -503,7 +665,7 @@ impl QuickJob {
        }
        if let Some(job) = self.small {
            let r = job.run();
-            return RenderResult { key, quick: Some(QuickSource::Small), ..r };
+            return RenderResult { request_id, key, quick: Some(QuickSource::Small), ..r };
        }
        done(Err("no quick preview".into()), None)
    }
@@ -521,11 +683,16 @@ pub fn content_key(p: &Photo) -> String {
 pub fn source_info(p: &Photo) -> SourceInfo {
    // Procedural demo scenes are scene-referred HDR (like raw files): use the filmic tone map.
    if matches!(p.source, Source::Demo { .. }) {
-        return SourceInfo { raw: true, as_shot_temp: 6500.0, as_shot_tint: 0.0, lens: None };
+        return SourceInfo { raw: true, ..Default::default() };
    }
    // A raw shown from its embedded preview is a rendered (display-referred) JPEG: relative white
    // balance and the display tone curve, like any other rendered file.
-    if p.develops_raw() { SourceInfo { raw: true, as_shot_temp: 5500.0, as_shot_tint: 0.0, lens: p.embedded_lens } } else { SourceInfo::default() }
+    if p.develops_raw() {
+        let (temp, tint) = if p.relative_wb() { (6500.0, 0.0) } else { p.as_shot_wb.unwrap_or((5500.0, 0.0)) };
+        SourceInfo { raw: true, as_shot_temp: temp, as_shot_tint: tint, lens: p.embedded_lens, relative_wb: p.relative_wb(), ..Default::default() }
+    } else {
+        SourceInfo::default()
+    }
 }

 impl crate::Session {
@@ -537,7 +704,7 @@ impl crate::Session {
    /// A grid/filmstrip thumbnail job: the long edge is rounded up to one of [`THUMB_SIZES`]
    /// (≥ `long_edge`) and the result comes from / goes to the thumbnail cache (memory + disk).
    pub fn thumb_job(&mut self, id: PhotoId, long_edge: usize) -> Option<RenderJob> {
-        let b = THUMB_SIZES.iter().copied().find(|s| *s >= long_edge).unwrap_or(THUMB_SIZES[THUMB_SIZES.len() - 1]);
+        let b = thumb_bucket(long_edge);
        self.build_job(id, b, b, false, true, Some(b))
    }

@@ -558,8 +725,12 @@ impl crate::Session {
        // the photo id is part of the key: two photos with the same settings and size must not
        // share a result (a view slot showing photo A would otherwise look current for photo B)
        // …and so is the file's content: a file changed on disk (Reload) renders afresh
-        let content = Hasher128::new().str(&content_key(&p)).finish().0 as u64;
-        let key = settings.hash64()
+        let content_key = content_key(&p);
+        let source_key = Hasher128::new().str(&content_key).finish();
+        let content = source_key.0 as u64;
+        // Temporary "before" settings must not replace the photo's cached develop hash.
+        let settings_hash = if before { settings.hash64() } else { self.media.settings_hashes.get(id, &settings) };
+        let key = settings_hash
            ^ ((max_w as u64) << 40)
            ^ ((max_h as u64) << 20)
            ^ (apply_crop as u64)
@@ -567,10 +738,19 @@ impl crate::Session {
            ^ id.0.wrapping_mul(0x9e37_79b9_7f4a_7c15)
            ^ content.rotate_left(17);
        let cache = thumb_bucket.map(|b| {
-            let k = Hasher128::new().str(&content_key(&p)).u64(settings.hash64()).u64(b as u64).u64(RENDER_CACHE_VERSION).finish();
+            let k = Hasher128::new()
+                .str(&content_key)
+                .u64(settings_hash)
+                .u64(b as u64)
+                .u64(RENDER_CACHE_VERSION)
+                .u64(crate::camera_profiles::cache_key())
+                .finish();
            (self.media.rendered.clone(), k)
        });
        Some(RenderJob {
+            request_id: 0,
+            cache_generation: self.media.rendered.generation(),
+            source_key: Some(source_key),
            photo: id,
            level,
            source,
@@ -596,7 +776,14 @@ impl crate::Session {

    /// Cache key of a variant thumbnail ([`Self::variant_job`]).
    pub fn variant_key(p: &Photo, settings: &DevelopSettings, edge: usize) -> Hash128 {
-        Hasher128::new().str(&content_key(p)).str("variant").u64(settings.hash64()).u64(edge as u64).u64(RENDER_CACHE_VERSION).finish()
+        Hasher128::new()
+            .str(&content_key(p))
+            .str("variant")
+            .u64(settings.hash64())
+            .u64(edge as u64)
+            .u64(RENDER_CACHE_VERSION)
+            .u64(crate::camera_profiles::cache_key())
+            .finish()
    }

    /// A thumbnail of `id` rendered with `settings` instead of its own (profile and preset
@@ -611,6 +798,9 @@ impl crate::Session {
        let source = self.media.source_ref(&p, level);
        let ck = Self::variant_key(&p, settings, edge);
        Some(RenderJob {
+            request_id: 0,
+            cache_generation: self.media.rendered.generation(),
+            source_key: Some(Hasher128::new().str(&content_key(&p)).finish()),
            photo: id,
            level,
            source,
@@ -625,9 +815,61 @@ impl crate::Session {
        })
    }

+    /// A square close-up of `face` (normalized, in the photo's upright frame) for a People card: the
+    /// photo's own look with its crop replaced by a square around the face (room for hair and chin),
+    /// `edge` pixels across (≤ 512). The source level is the smallest that keeps the face sharp, up
+    /// to the preview. Cached like [`Self::variant_job`], and `key` likewise follows the content.
+    pub fn face_job(&mut self, id: PhotoId, face: lightcraft_geom::Rect, edge: usize) -> Option<RenderJob> {
+        let p = self.catalog.photo(id)?.clone();
+        // `face` is on the upright (EXIF-oriented) photo; the crop below is in the frame after the
+        // user's Rotate Left/Right, so carry the box (and the photo's size) over to it.
+        let orient = p.develop.orientation;
+        let face = orient.map_norm_rect(face);
+        let (w, h) = (f64::from(p.width.max(1)), f64::from(p.height.max(1)));
+        let (w, h) = if orient.swaps_axes() { (h, w) } else { (w, h) };
+        let side = ((face.x1 - face.x0) * w).max((face.y1 - face.y0) * h) * 1.7;
+        // finite, within the photo, and never wider than its short side (so the clamps below are valid)
+        let side = if side.is_finite() { side.clamp(1.0, w.min(h)) } else { w.min(h) };
+        let (cx, cy) = ((face.x0 + face.x1) / 2.0 * w, (face.y0 + face.y1) / 2.0 * h);
+        let (cx, cy) = (if cx.is_finite() { cx } else { w / 2.0 }, if cy.is_finite() { cy } else { h / 2.0 });
+        let (x0, y0) = (cx.clamp(side / 2.0, w - side / 2.0) - side / 2.0, cy.clamp(side / 2.0, h - side / 2.0) - side / 2.0);
+        let rect = lightcraft_geom::Rect { x0: x0 / w, y0: y0 / h, x1: (x0 + side) / w, y1: (y0 + side) / h };
+        let mut settings = (*p.develop).clone();
+        settings.crop = lightcraft_develop::Crop { geometry: lightcraft_geom::CropGeometry { rect, angle: 0.0 }, ..Default::default() };
+        let edge = edge.clamp(16, SourceLevel::Thumb.max_edge());
+        // pixels along the long edge that leave `edge` across the crop
+        let needed = (edge as f64 * w.max(h) / side).ceil().min(SourceLevel::Preview.max_edge() as f64);
+        let level = SourceLevel::for_size(needed as usize);
+        let source = self.media.source_ref(&p, level);
+        let ck = Self::variant_key(&p, &settings, edge);
+        Some(RenderJob {
+            request_id: 0,
+            cache_generation: self.media.rendered.generation(),
+            source_key: Some(Hasher128::new().str(&content_key(&p)).finish()),
+            photo: id,
+            level,
+            source,
+            origin: p.source.clone(),
+            info: source_info(&p),
+            settings: Arc::new(settings),
+            request: RenderRequest { apply_crop: true, ..RenderRequest::fit(edge, edge) },
+            key: (ck.0 as u64) ^ ((ck.0 >> 64) as u64),
+            cache: Some((self.media.rendered.clone(), ck)),
+            stages: None,
+            view_cache: None,
+        })
+    }
+
    /// Size-independent cache key of a photo's view render (loupe) for its current settings.
    fn view_key(p: &Photo, apply_crop: bool) -> Hash128 {
-        Hasher128::new().str(&content_key(p)).str("view").u64(p.develop.hash64()).u64(apply_crop as u64).u64(RENDER_CACHE_VERSION).finish()
+        Hasher128::new()
+            .str(&content_key(p))
+            .str("view")
+            .u64(p.develop.hash64())
+            .u64(apply_crop as u64)
+            .u64(RENDER_CACHE_VERSION)
+            .u64(crate::camera_profiles::cache_key())
+            .finish()
    }

    /// The loupe's render job: like [`Self::render_job`], and a full-quality result is kept as the
@@ -657,7 +899,7 @@ impl crate::Session {
        let h = Hasher128::new().str(&content_key(&p)).str("quick").u64(p.develop.hash64()).u64(apply_crop as u64).finish();
        let key = h.0 as u64;
        let embedded = self.embedded_of(&p).map(|(path, l)| (path, l, max_edge.clamp(1, SourceLevel::Preview.max_edge())));
-        Some(QuickJob { photo: id, key, cached, embedded, small: apply_crop.then(|| Box::new(small)) })
+        Some(QuickJob { request_id: 0, photo: id, key, cached, embedded, small: apply_crop.then(|| Box::new(small)) })
    }

    /// A first grid thumbnail for an unedited raw: the cached render for `job` (the real
@@ -669,6 +911,7 @@ impl crate::Session {
        let (path, l) = self.embedded_of(&p)?;
        let edge = job.request.max_w.max(job.request.max_h);
        Some(QuickJob {
+            request_id: 0,
            photo: job.photo,
            key: job.key,
            cached: job.cache.clone().into_iter().collect(),
@@ -679,8 +922,10 @@ impl crate::Session {

    /// Accept a finished job's loaded source into the cache.
    pub fn accept(&mut self, r: &RenderResult) {
-        if let Some(src) = &r.loaded {
-            self.media.insert(r.photo, r.level, src.clone());
+        if let Some(src) = &r.loaded
+            && r.source_key.is_none_or(|key| self.catalog.photo(r.photo).is_some_and(|p| Hasher128::new().str(&content_key(p)).finish() == key))
+        {
+            self.media.insert_source(r.photo, r.level, src.clone());
        }
    }

@@ -723,12 +968,19 @@ impl crate::Session {
        Ok(job)
    }

+    /// Prefer decoder facts to header-only metadata for pixel-statistics commands.
+    pub fn source_info(&self, id: PhotoId) -> SourceInfo {
+        let header = self.catalog.photo(id).map(|p| source_info(p)).unwrap_or_default();
+        self.media.source_facts(id, header)
+    }
+
    /// The source proxy for pixel-statistics commands (auto tone/WB), loading synchronously.
    pub fn source_now(&mut self, id: PhotoId, level: SourceLevel) -> Result<Arc<Rgb32f>, String> {
        let p = self.catalog.photo(id).ok_or("no such photo")?.clone();
-        let r = self.media.source_ref(&p, level).load()?;
-        self.media.insert(id, level, r.clone());
-        Ok(r)
+        let r = self.media.source_ref(&p, level).load_source()?;
+        let image = r.image.clone();
+        self.media.insert_source(id, level, r);
+        Ok(image)
    }
 }

@@ -743,7 +995,9 @@ pub struct ProbeInfo {
    pub captured: Option<String>,
    pub meta: lightcraft_catalog::Meta,
    pub as_shot_wb: Option<(f64, f64)>,
-    /// Hash of the file's bytes (hex), for duplicate detection.
+    /// Hash of the file's bytes (hex), for duplicate detection. When it is a 32-digit
+    /// [`lightcraft_preview::hash_bytes`] of the whole file (as the native probe computes it),
+    /// Import → Copy verifies each copy against it instead of reading the source again.
    pub content_hash: Option<String>,
    /// Lens corrections embedded in the file (DNG opcodes).
    pub embedded_lens: Option<lightcraft_develop::EmbeddedLens>,
@@ -756,10 +1010,141 @@ pub struct ProbeInfo {

 pub type FileProbe = Arc<dyn Fn(&str) -> Result<ProbeInfo, String> + Send + Sync>;

+#[cfg(test)]
+mod thumbnail_hash_tests {
+    use super::*;
+    use lightcraft_catalog::Op;
+
+    fn session() -> crate::Session {
+        let mut s = crate::Session::new();
+        let p = Photo::new(PhotoId(1), Source::File { path: "hash-fixture.jpg".into() }, "fixture.jpg", "JPEG", 6000, 4000, "2026-01-01");
+        s.catalog.apply(Op::AddPhoto { photo: Box::new(p) }).unwrap();
+        s
+    }
+    #[test]
+    fn hashes_match_uncached_keys_and_are_not_recomputed_for_sizes_metadata_or_before() {
+        let mut s = session();
+        for edge in [256, 384, 512, 256] {
+            let p = s.catalog.photo(PhotoId(1)).unwrap().clone();
+            let b = thumb_bucket(edge);
+            // Independent original formula: never asks the new hash cache for expected values.
+            let settings = p.develop.hash64();
+            let content = Hasher128::new().str(&content_key(&p)).finish().0 as u64;
+            let expected =
+                settings ^ ((b as u64) << 40) ^ ((b as u64) << 20) ^ 1 ^ p.id.0.wrapping_mul(0x9e37_79b9_7f4a_7c15) ^ content.rotate_left(17);
+            let disk = Hasher128::new()
+                .str(&content_key(&p))
+                .u64(settings)
+                .u64(b as u64)
+                .u64(RENDER_CACHE_VERSION)
+                .u64(crate::camera_profiles::cache_key())
+                .finish();
+            let job = s.thumb_job(p.id, edge).unwrap();
+            assert_eq!(job.key, expected);
+            assert_eq!(job.cache.unwrap().1, disk);
+        }
+        s.catalog.apply(Op::SetRating { id: PhotoId(1), rating: 4 }).unwrap();
+        s.thumb_job(PhotoId(1), 256).unwrap();
+        s.render_job(PhotoId(1), 256, 256, true, true).unwrap();
+        s.thumb_job(PhotoId(1), 256).unwrap();
+        assert_eq!(s.media.settings_hashes.computations, 1);
+        let mut edit = DevelopSettings::default();
+        edit.light.exposure = 1.0;
+        let undo = s.catalog.apply(Op::SetDevelop { id: PhotoId(1), settings: Arc::new(edit), label: "edit".into(), edited: None }).unwrap();
+        s.thumb_job(PhotoId(1), 256).unwrap();
+        s.thumb_job(PhotoId(1), 384).unwrap();
+        assert_eq!(s.media.settings_hashes.computations, 2);
+        s.catalog.apply(undo).unwrap();
+        s.thumb_job(PhotoId(1), 256).unwrap();
+        assert_eq!(s.media.settings_hashes.computations, 3);
+    }
+    #[test]
+    fn hash_cache_is_bounded_weak_and_shared_settings_remain_independent() {
+        let mut hashes = SettingsHashes::default();
+        let shared = Arc::new(DevelopSettings::default());
+        for id in 1..=SETTINGS_HASH_ENTRIES as u64 * 3 {
+            assert_eq!(hashes.get(PhotoId(id), &shared), shared.hash64());
+        }
+        assert_eq!(hashes.entries.len(), SETTINGS_HASH_ENTRIES);
+        assert_eq!(hashes.order.len(), SETTINGS_HASH_ENTRIES);
+        assert_eq!(Arc::strong_count(&shared), 1);
+        let mut edit = (*shared).clone();
+        edit.light.exposure = 1.0;
+        let edit = Arc::new(edit);
+        let a = PhotoId(10000);
+        let b = PhotoId(10001);
+        let initial = hashes.get(a, &shared);
+        assert_eq!(hashes.get(b, &shared), initial);
+        assert_ne!(hashes.get(a, &edit), initial);
+        assert_eq!(hashes.get(b, &shared), initial);
+        let mut s = session();
+        s.thumb_job(PhotoId(1), 256).unwrap();
+        s.media.clear_sources();
+        assert!(s.media.settings_hashes.entries.is_empty());
+        assert!(s.media.settings_hashes.order.is_empty());
+    }
+    #[test]
+    fn source_from_before_content_reload_is_not_accepted() {
+        let mut s = session();
+        s.media.file_loader = Some(Arc::new(|_, _| Ok((Rgb32f::new(8, 8), SourceInfo::default()))));
+        let old = s.thumb_job(PhotoId(1), 256).unwrap().run();
+        assert!(old.loaded.is_some());
+        s.catalog
+            .apply(Op::SetContent {
+                id: PhotoId(1),
+                width: 6000,
+                height: 4000,
+                file_size: 99,
+                content_hash: Some("replacement".into()),
+                preview_only: None,
+            })
+            .unwrap();
+        s.media.forget(PhotoId(1));
+        s.accept(&old);
+        assert_eq!(s.media.source_usage().0, 0);
+    }
+}
+
 #[cfg(test)]
 mod tests {
    use super::*;

+    #[test]
+    fn decoder_info_survives_render_jobs_cache_and_eviction() {
+        let tone = lightcraft_pipeline::tone::CameraTone::new(std::array::from_fn(|i| {
+            let x = 0.01 * (i + 1) as f32;
+            [x, (x * 2.0).min(0.9)]
+        }))
+        .unwrap();
+        let info = SourceInfo { raw: true, relative_wb: true, camera_tone: Some(tone), ..Default::default() };
+        let mut s = crate::Session::with_demo();
+        let id = s.active().unwrap();
+        let mut job = s.render_job(id, 64, 64, false, true).unwrap();
+        job.source = SourceRef::File {
+            path: "synthetic.arw".into(),
+            max_edge: 64,
+            loader: Some(Arc::new(move |_, _| {
+                let mut image = Rgb32f::new(64, 64);
+                image.data.fill([0.1; 3]);
+                Ok((image, info))
+            })),
+            fallback: None,
+        };
+        job.info = SourceInfo::default(); // Header facts cannot override decoder facts.
+        job.settings = Arc::new(DevelopSettings::default());
+        let r = job.clone().run();
+        assert_eq!(r.loaded.as_ref().unwrap().info, Some(info));
+        let expected = lightcraft_pipeline::render(&r.loaded.as_ref().unwrap().image, &info, &job.settings, &job.request);
+        assert_eq!(r.rendered.as_ref().unwrap().image.data, expected.image.data);
+        s.accept(&r);
+        job.source = s.media.source_ref(s.catalog.photo(id).unwrap(), job.level);
+        let again = job.run();
+        assert!(again.loaded.is_none());
+        assert_eq!(r.rendered.unwrap().image.data, again.rendered.unwrap().image.data);
+        s.media.forget(id);
+        assert!(s.media.get_source(id, r.level).is_none());
+    }
+
    #[test]
    fn budget_evicts_least_recently_used_across_caches() {
        let img = |w: usize| Arc::new(Rgb32f::new(w, w));
@@ -15,6 +15,8 @@ use lightcraft_catalog::{Catalog, Source};
 pub struct OriginalGuard {
    /// lower-case file name → (path on disk, what it is: "the original of IMG_1.CR3", …)
    by_name: HashMap<String, Vec<(PathBuf, String)>>,
+    /// The entries of `by_name` that are symlinks, found on the first check that needs them.
+    links: std::sync::OnceLock<Vec<(PathBuf, String)>>,
 }

 impl OriginalGuard {
@@ -32,6 +34,7 @@ impl OriginalGuard {
    /// Protect `path` (an original named `label`) and its sidecars (`IMG_1.xmp`, `IMG_1.CR3.xmp`).
    pub fn add(&mut self, path: &Path, label: &str) {
        let Some(name) = path.file_name().map(|n| n.to_string_lossy().to_string()) else { return };
+        self.links = std::sync::OnceLock::new();
        let mut put = |file: String, p: PathBuf, what: String| self.by_name.entry(file.to_lowercase()).or_default().push((p, what));
        put(name.clone(), path.to_path_buf(), format!("the original of {label}"));
        let stem = path.file_stem().map(|s| s.to_string_lossy().to_string()).unwrap_or_default();
@@ -58,6 +61,19 @@ impl OriginalGuard {
                }
            }
        }
+        // An imported symlink can have a different name from its original. A write to
+        // that original would change what the library reads through the link. Only do
+        // this fallback for existing targets that the name index did not protect; the links are
+        // looked up once per guard, not once per target.
+        let links = self.links.get_or_init(|| self.by_name.values().flatten().filter(|(p, _)| std::fs::read_link(p).is_ok()).cloned().collect());
+        for (p, what) in links {
+            if same_file(p, target) {
+                return Err(format!(
+                    "{} is {what} in the library: LightCraft never writes over an original (choose another folder or file name)",
+                    target.display()
+                ));
+            }
+        }
        Ok(())
    }
 }
@@ -68,9 +84,14 @@ impl crate::Session {
        OriginalGuard::new(&self.catalog)
    }

-    /// `Err` when writing `path` would replace a catalogued photo's original or sidecar.
+    /// `Err` when writing `path` would replace a catalogued photo's original or sidecar. A free
+    /// path (the usual case) is answered without building the guard over the whole library.
    pub fn check_write_target(&self, path: &str) -> Result<(), String> {
-        self.original_guard().check(Path::new(path))
+        let path = Path::new(path);
+        if std::fs::symlink_metadata(path).is_err() {
+            return Ok(()); // nothing there to replace
+        }
+        self.original_guard().check(path)
    }
 }

@@ -100,6 +100,7 @@ impl Lua {
 struct LuaParser<'a> {
    s: &'a [u8],
    i: usize,
+    depth: usize,
 }

 impl LuaParser<'_> {
@@ -210,6 +211,15 @@ impl LuaParser<'_> {
        std::str::from_utf8(&self.s[start..self.i]).ok().and_then(|t| t.parse().ok()).map_or_else(|| self.err("bad number"), Ok)
    }
    fn value(&mut self) -> Result<Lua, String> {
+        if self.depth >= 64 {
+            return self.err("Lua settings exceed nesting limit");
+        }
+        self.depth += 1;
+        let result = self.value_inner();
+        self.depth -= 1;
+        result
+    }
+    fn value_inner(&mut self) -> Result<Lua, String> {
        self.skip_ws();
        let Some(&c) = self.s.get(self.i) else { return self.err("unexpected end") };
        match c {
@@ -315,7 +325,10 @@ impl LuaParser<'_> {

 /// Parse a Lua table literal, optionally preceded by `name =` or `return`.
 pub fn parse_lua(text: &str) -> Result<Lua, String> {
-    let mut p = LuaParser { s: text.as_bytes(), i: 0 };
+    if text.len() > 16 << 20 {
+        return Err("Lua settings exceed 16 MiB".into());
+    }
+    let mut p = LuaParser { s: text.as_bytes(), i: 0, depth: 0 };
    p.skip_ws();
    let save = p.i;
    match p.ident().as_deref() {
@@ -347,6 +360,12 @@ pub fn lrtemplate_props(text: &str) -> Result<(Option<String>, Props, crate::crs
    let root = parse_lua(text)?;
    let title = root.get("title").or_else(|| root.get("internalName")).and_then(Lua::str).map(delocalize).filter(|t| !t.trim().is_empty());
    let settings = root.get("value").and_then(|v| v.get("settings")).ok_or("no develop settings in this template")?;
+    let (props, values) = lua_settings_props(settings)?;
+    Ok((title, props, values))
+}
+
+/// Data-only Lua settings shared by preset and native catalog import. Never executes Lua.
+pub(crate) fn lua_settings_props(settings: &Lua) -> Result<(Props, crate::crs_masks::Values), String> {
    let Lua::Table(_, fields) = settings else { return Err("no develop settings in this template".into()) };
    let mut props = Props::new();
    let mut values = crate::crs_masks::Values::new();
@@ -374,7 +393,7 @@ pub fn lrtemplate_props(text: &str) -> Result<(Option<String>, Props, crate::crs
        };
        props.insert(key, vals);
    }
-    Ok((title, props, values))
+    Ok((props, values))
 }

 // ------------------------------------------------------------------------------- XMP in files
@@ -83,28 +83,22 @@ pub fn parse_preset_file(name: &str, bytes: &[u8]) -> Result<Vec<Preset>, String
    Ok(out)
 }

-/// Expand files/folders (recursively) into preset files (`.lcpreset`, `.xmp`).
+/// Expand files/folders (recursively, bounded: see [`crate::walk`]) into preset files
+/// (`.lcpreset`, `.xmp`).
 pub fn expand_preset_paths(paths: &[String]) -> Vec<String> {
-    fn walk(p: &Path, out: &mut Vec<String>, top: bool) {
-        if p.is_dir() {
-            let Ok(rd) = std::fs::read_dir(p) else { return };
-            let mut v: Vec<_> = rd.flatten().map(|e| e.path()).collect();
-            v.sort();
-            for c in v {
-                if !c.file_name().is_some_and(|n| n.to_string_lossy().starts_with('.')) {
-                    walk(&c, out, false);
-                }
-            }
-        } else {
-            let ext = p.extension().map(|e| e.to_string_lossy().to_ascii_lowercase()).unwrap_or_default();
-            if top || ext == LCPRESET_EXT || ["xmp", "lrtemplate", "zip", "lmp", "mplumpack"].contains(&ext.as_str()) {
-                out.push(p.to_string_lossy().to_string());
-            }
-        }
-    }
+    let preset_file = |p: &Path| {
+        let ext = p.extension().map(|e| e.to_string_lossy().to_ascii_lowercase()).unwrap_or_default();
+        ext == LCPRESET_EXT || ["xmp", "lrtemplate", "zip", "lmp", "mplumpack"].contains(&ext.as_str())
+    };
    let mut out = Vec::new();
    for p in paths {
-        walk(Path::new(p), &mut out, true);
+        let path = Path::new(p);
+        if path.is_dir() {
+            let w = crate::walk::files_in(path, None, crate::walk::Limits::default(), preset_file);
+            out.extend(w.files.into_iter().map(|f| f.to_string_lossy().to_string()));
+        } else {
+            out.push(p.clone());
+        }
    }
    out
 }
@@ -446,6 +440,14 @@ pub fn profile(id: &str) -> Option<&'static ProfileInfo> {
 pub const RECENT_PROFILES: usize = 5;

 impl Session {
+    /// A profile by id, looking up built-in profiles first and imported LUT profiles second.
+    pub fn profile_info(&self, id: &str) -> Option<(&str, &str)> {
+        if let Some(p) = profile(id) {
+            return Some((p.name, p.group));
+        }
+        self.lut_profiles.iter().find(|p| p.id == id).map(|p| (p.name.as_str(), p.group.as_str()))
+    }
+
    /// Remember `id` as the most recently applied profile.
    pub fn note_profile_used(&mut self, id: &str) {
        self.profile_recent.retain(|p| p != id);
@@ -395,7 +395,12 @@ impl MoveFs for RealFs {
 /// `from` → `to` differs only in letter case and `to` is that very file (a case-insensitive
 /// volume): the rename must go through a temporary name.
 fn is_respelling(fs: &dyn MoveFs, from: &Path, to: &Path) -> bool {
-    from != to && from.to_string_lossy().to_lowercase() == to.to_string_lossy().to_lowercase() && fs.exists(to) && fs.same_file(from, to)
+    from != to && folded_path(&from.to_string_lossy()) == folded_path(&to.to_string_lossy()) && fs.exists(to) && fs.same_file(from, to)
+}
+
+/// Windows accepts both separators; spelling differences must not hide file identity.
+fn folded_path(path: &str) -> String {
+    if cfg!(windows) { path.replace('\\', "/").to_lowercase() } else { path.to_lowercase() }
 }

 /// Rename `a` to `b` without ever replacing a file; a change of letter case only goes through a
@@ -439,7 +444,7 @@ pub fn move_file(from: &str, to: &str) -> std::result::Result<(), MoveError> {

 /// [`move_file`] on the file system `fs`.
 pub(crate) fn move_file_with(fs: &dyn MoveFs, from: &str, to: &str) -> std::result::Result<(), MoveError> {
-    if from == to {
+    if Path::new(from) == Path::new(to) {
        return Ok(());
    }
    let fail = |message: String| MoveError { message, moved: false };
@@ -538,6 +543,92 @@ fn set_file_ops_to(op: &Op, to: &HashSet<&str>, out: &mut Vec<Op>) {
    }
 }

+/// The photos among `ids` a rename handles, in order: photos sharing one file (virtual copies)
+/// rename once. No file-system calls.
+pub fn rename_photos(cat: &lightcraft_catalog::Catalog, ids: &[PhotoId]) -> Vec<std::sync::Arc<Photo>> {
+    let mut seen_paths: HashSet<String> = HashSet::new();
+    ids.iter()
+        .filter_map(|id| cat.photo(*id))
+        .filter(|p| match &p.source {
+            Source::File { path } => seen_paths.insert(path.clone()),
+            _ => true,
+        })
+        .cloned()
+        .collect()
+}
+
+/// [`Session::plan_rename`] for [`rename_photos`], with the "is this name taken on disk?" check
+/// supplied: the Rename dialog plans its preview on a worker thread (a check can block on a slow
+/// drive). Whether a case-only change names this very file is decided on the disk.
+pub fn plan_rename_photos(photos: &[std::sync::Arc<Photo>], template: &str, start: usize, exists: &dyn Fn(&str) -> bool) -> Vec<RenamePlan> {
+    plan_rename_core(photos, template, start, &|p| exists(&p.to_string_lossy()), &|a, b| RealFs.same_file(a, b))
+}
+
+/// Plan renaming `photos`: `exists` says whether something answers to a path, `same_file` whether
+/// two spellings name one file (see [`MoveFs`]).
+fn plan_rename_core(
+    photos: &[std::sync::Arc<Photo>],
+    template: &str,
+    start: usize,
+    exists: &dyn Fn(&Path) -> bool,
+    same_file: &dyn Fn(&Path, &Path) -> bool,
+) -> Vec<RenamePlan> {
+    let mut taken: HashSet<String> = HashSet::new(); // lower-case target paths/names claimed in this batch
+    let mut out = Vec::new();
+    for (seq, p) in (start..).zip(photos) {
+        let want = expand(template, p, seq);
+        let (stem, ext) = split_ext(&want);
+        let (stem, ext) = (stem.to_string(), ext.to_string());
+        let candidate = |k: usize| {
+            if k == 0 {
+                want.clone()
+            } else if ext.is_empty() {
+                format!("{stem}-{k}")
+            } else {
+                format!("{stem}-{k}.{ext}")
+            }
+        };
+        let (to, to_path) = match &p.source {
+            Source::File { path } => {
+                let dir = Path::new(path).parent().map(Path::to_path_buf).unwrap_or_default();
+                let mut k = 0;
+                loop {
+                    let name = candidate(k);
+                    let tp = dir.join(&name).to_string_lossy().to_string();
+                    let key = folded_path(&tp);
+                    // this very file, maybe spelled differently (case-insensitive volume)? By
+                    // identity: on a case-sensitive volume `img_1.jpg` may be another photo
+                    let (from, to) = (Path::new(path), Path::new(&tp));
+                    let same = from == to || (key == folded_path(path) && exists(to) && same_file(from, to));
+                    // free: not claimed in this batch and not on disk (unless it is this very file).
+                    // A file this batch moves away still counts as taken: simple and safe.
+                    if !taken.contains(&key) && (same || !exists(to)) {
+                        taken.insert(key);
+                        break (name, Some(tp));
+                    }
+                    k += 1;
+                }
+            }
+            Source::Demo { .. } => {
+                let mut k = 0;
+                loop {
+                    let name = candidate(k);
+                    if taken.insert(format!("demo:{}", name.to_lowercase())) {
+                        break (name, None);
+                    }
+                    k += 1;
+                }
+            }
+        };
+        let from_path = match &p.source {
+            Source::File { path } => Some(path.clone()),
+            _ => None,
+        };
+        out.push(RenamePlan { id: p.id.0, from: p.file_name.clone(), to, from_path, to_path });
+    }
+    out
+}
+
 impl Session {
    /// Plan renaming `ids` with `template` (sequence numbers from `start`), resolving collisions.
    pub fn plan_rename(&self, ids: &[PhotoId], template: &str, start: usize) -> Vec<RenamePlan> {
@@ -546,70 +637,7 @@ impl Session {

    /// [`Session::plan_rename`] on the file system `fs`.
    pub(crate) fn plan_rename_with(&self, fs: &dyn MoveFs, ids: &[PhotoId], template: &str, start: usize) -> Vec<RenamePlan> {
-        // photos sharing one file (virtual copies) rename once
-        let mut seen_paths: HashSet<String> = HashSet::new();
-        let mut taken: HashSet<String> = HashSet::new(); // lower-case target paths/names claimed in this batch
-        let mut out = Vec::new();
-        let mut seq = start;
-        for id in ids {
-            let Some(p) = self.catalog.photo(*id) else { continue };
-            if let Source::File { path } = &p.source
-                && !seen_paths.insert(path.clone())
-            {
-                continue;
-            }
-            let want = expand(template, p, seq);
-            seq += 1;
-            let (stem, ext) = split_ext(&want);
-            let (stem, ext) = (stem.to_string(), ext.to_string());
-            let candidate = |k: usize| {
-                if k == 0 {
-                    want.clone()
-                } else if ext.is_empty() {
-                    format!("{stem}-{k}")
-                } else {
-                    format!("{stem}-{k}.{ext}")
-                }
-            };
-            let (to, to_path) = match &p.source {
-                Source::File { path } => {
-                    let dir = Path::new(path).parent().map(Path::to_path_buf).unwrap_or_default();
-                    let mut k = 0;
-                    loop {
-                        let name = candidate(k);
-                        let tp = dir.join(&name).to_string_lossy().to_string();
-                        let key = tp.to_lowercase();
-                        // this very file, maybe spelled differently (case-insensitive volume)? By
-                        // identity: on a case-sensitive volume `img_1.jpg` may be another photo
-                        let same = tp == *path || is_respelling(fs, Path::new(path), Path::new(&tp));
-                        // free: not claimed in this batch and not on disk (unless it is this very file).
-                        // A file this batch moves away still counts as taken: simple and safe.
-                        let on_disk = fs.exists(Path::new(&tp)) && !same;
-                        if !taken.contains(&key) && !on_disk {
-                            taken.insert(key);
-                            break (name, Some(tp));
-                        }
-                        k += 1;
-                    }
-                }
-                Source::Demo { .. } => {
-                    let mut k = 0;
-                    loop {
-                        let name = candidate(k);
-                        if taken.insert(format!("demo:{}", name.to_lowercase())) {
-                            break (name, None);
-                        }
-                        k += 1;
-                    }
-                }
-            };
-            let from_path = match &p.source {
-                Source::File { path } => Some(path.clone()),
-                _ => None,
-            };
-            out.push(RenamePlan { id: id.0, from: p.file_name.clone(), to, from_path, to_path });
-        }
-        out
+        plan_rename_core(&rename_photos(&self.catalog, ids), template, start, &|p| fs.exists(p), &|a, b| fs.same_file(a, b))
    }

    /// Carry out `plans`: move the files (rolled back on failure), then commit one undoable op
@@ -633,6 +661,7 @@ impl Session {
            };
            let Some(plan) = plan else { continue };
            let source = match &plan.to_path {
+                Some(t) if matches!(&p.source, Source::File { path } if Path::new(path) == Path::new(t)) => p.source.clone(),
                Some(t) => Source::File { path: t.clone() },
                None => p.source.clone(),
            };
@@ -645,7 +674,7 @@ impl Session {
        let moves: Vec<(String, String)> = plans
            .iter()
            .filter_map(|pl| match (&pl.from_path, &pl.to_path) {
-                (Some(a), Some(b)) if a != b => Some((a.clone(), b.clone())),
+                (Some(a), Some(b)) if Path::new(a) != Path::new(b) => Some((a.clone(), b.clone())),
                _ => None,
            })
            .collect();
@@ -709,7 +738,7 @@ impl Session {
                Op::Batch { ops } => ops.iter().for_each(|o| rec(s, o, v)),
                Op::SetFile { id, source: Source::File { path: to }, .. } => {
                    if let Some(Source::File { path: from }) = s.catalog.photo(*id).map(|p| &p.source)
-                        && from != to
+                        && Path::new(from) != Path::new(to)
                        && !v.iter().any(|(f, _)| f == from)
                    {
                        v.push((from.clone(), to.clone()));
@@ -745,13 +774,17 @@ mod tests {
                fail: RefCell::new(Vec::new()),
            }
        }
+        /// The model volume spells paths with `/`; the code under test joins them with the host's separator.
+        fn norm(p: &Path) -> String {
+            p.to_string_lossy().replace('\\', "/")
+        }
        fn idx(&self, p: &Path) -> Option<usize> {
-            let p = p.to_string_lossy();
-            self.files.borrow().iter().position(|(f, _)| if self.ci { f.to_lowercase() == p.to_lowercase() } else { *f == p })
+            let p = Self::norm(p);
+            self.files.borrow().iter().position(|(f, _)| if self.ci { folded_path(f) == folded_path(&p) } else { *f == p })
        }
        /// The listing: (exact path, contents), sorted.
        pub fn listing(&self) -> Vec<(String, String)> {
-            let mut v: Vec<_> = self.files.borrow().iter().map(|(p, c)| (p.clone(), String::from_utf8_lossy(c).to_string())).collect();
+            let mut v: Vec<_> = self.files.borrow().iter().map(|(p, c)| (p.replace('\\', "/"), String::from_utf8_lossy(c).to_string())).collect();
            v.sort();
            v
        }
@@ -768,14 +801,14 @@ mod tests {
            self.idx(a).is_some() && self.idx(a) == self.idx(b)
        }
        fn rename_no_replace(&self, a: &Path, b: &Path) -> std::io::Result<()> {
-            if self.fail.borrow().iter().any(|f| a.to_string_lossy().contains(f.as_str())) {
+            if self.fail.borrow().iter().any(|f| Self::norm(a).contains(f.as_str())) {
                return Err(std::io::Error::other("injected failure"));
            }
            if self.exists(b) {
                return Err(std::io::Error::new(std::io::ErrorKind::AlreadyExists, "exists"));
            }
            let i = self.idx(a).ok_or_else(|| std::io::Error::new(std::io::ErrorKind::NotFound, "no such file"))?;
-            self.files.borrow_mut()[i].0 = b.to_string_lossy().to_string();
+            self.files.borrow_mut()[i].0 = Self::norm(b);
            Ok(())
        }
        fn copy_no_replace(&self, a: &Path, b: &Path) -> std::io::Result<()> {
@@ -784,7 +817,7 @@ mod tests {
            }
            let i = self.idx(a).ok_or_else(|| std::io::Error::new(std::io::ErrorKind::NotFound, "no such file"))?;
            let c = self.files.borrow()[i].1.clone();
-            self.files.borrow_mut().push((b.to_string_lossy().to_string(), c));
+            self.files.borrow_mut().push((Self::norm(b), c));
            Ok(())
        }
        fn remove_file(&self, p: &Path) -> std::io::Result<()> {
@@ -793,17 +826,64 @@ mod tests {
            Ok(())
        }
        fn stem_sibling(&self, sidecar: &Path) -> Option<String> {
-            let stem = sidecar.with_extension("").to_string_lossy().to_string();
+            let stem = Self::norm(&sidecar.with_extension(""));
            self.files.borrow().iter().map(|(f, _)| f.clone()).find(|f| {
                let p = Path::new(f);
-                p.with_extension("").to_string_lossy() == stem && !p.extension().is_some_and(|e| e.eq_ignore_ascii_case("xmp"))
+                Self::norm(&p.with_extension("")) == stem && !p.extension().is_some_and(|e| e.eq_ignore_ascii_case("xmp"))
            })
        }
    }

    fn file_photo(id: u64, path: &str) -> Photo {
        let name = Path::new(path).file_name().map(|n| n.to_string_lossy().to_string()).unwrap_or_default();
-        Photo::new(PhotoId(id), Source::File { path: path.into() }, &name, "JPG", 1, 1, "2026-01-01T00:00:00")
+        // the host's separator, so `dir.join(name)` in the planner spells the same path the same way
+        let path = path.replace('/', std::path::MAIN_SEPARATOR_STR);
+        Photo::new(PhotoId(id), Source::File { path }, &name, "JPG", 1, 1, "2026-01-01T00:00:00")
+    }
+
+    #[cfg(windows)]
+    #[test]
+    fn mixed_separator_noop_rename_preserves_files_catalog_and_undo() {
+        let fs = FakeFs::new(true, &[("N:/photos/IMG.jpg", "image"), ("N:/photos/IMG.xmp", "edits"), ("N:/photos/other.jpg", "other")]);
+        // Any attempt to move the unchanged photo (including rollback) must fail.
+        fs.fail.borrow_mut().push("IMG".into());
+        let mut s = Session::new();
+        // spelled with `/` on purpose (not `file_photo`, which uses the host's separator)
+        for (id, path) in [(1, "N:/photos/IMG.jpg"), (2, "N:/photos/other.jpg")] {
+            let name = Path::new(path).file_name().map(|n| n.to_string_lossy().to_string()).unwrap_or_default();
+            let photo = Photo::new(PhotoId(id), Source::File { path: path.into() }, &name, "JPG", 1, 1, "2026-01-01T00:00:00");
+            s.catalog.apply(Op::AddPhoto { photo: Box::new(photo) }).unwrap();
+        }
+        let before = fs.listing();
+        let plans = s.plan_rename_with(&fs, &[PhotoId(1)], "{name}", 1);
+        assert_ne!(plans[0].from_path, plans[0].to_path, "fixture exercises different separator spelling");
+        assert_eq!(s.apply_rename_with(&fs, &plans).unwrap(), 0);
+        assert_eq!(fs.listing(), before);
+        assert_eq!(s.catalog.photo(PhotoId(1)).unwrap().source, Source::File { path: "N:/photos/IMG.jpg".into() });
+        assert!(s.undo.is_empty());
+        move_file_with(&fs, "N:/photos/IMG.jpg", "N:/photos\\IMG.jpg").unwrap();
+        let separator_only = Op::SetFile { id: PhotoId(1), file_name: "IMG.jpg".into(), source: Source::File { path: "N:/photos\\IMG.jpg".into() } };
+        assert!(s.file_moves(&separator_only).is_empty());
+
+        // A batch may combine that no-op with a genuine rename, without touching IMG or its sidecar.
+        let mut batch = plans;
+        batch.extend(s.plan_rename_with(&fs, &[PhotoId(2)], "renamed", 1));
+        assert_eq!(s.apply_rename_with(&fs, &batch).unwrap(), 1);
+        assert_eq!(
+            fs.listing(),
+            vec![
+                ("N:/photos/IMG.jpg".into(), "image".into()),
+                ("N:/photos/IMG.xmp".into(), "edits".into()),
+                ("N:/photos/renamed.jpg".into(), "other".into())
+            ]
+        );
+        let undo = &s.undo.last().unwrap().op;
+        let moves = s.file_moves(undo);
+        assert_eq!(moves.len(), 1);
+        assert_eq!(Path::new(&moves[0].1), Path::new("N:/photos/other.jpg"));
+        move_all(&fs, &moves).unwrap();
+        s.catalog.apply(undo.clone()).unwrap();
+        assert_eq!(fs.listing(), before);
    }

    /// Issue #95: a case-only rename is a real change on a case-insensitive volume and never
@@ -861,7 +941,7 @@ mod tests {
        let plans = s.plan_rename_with(&fs, &ids, "Trip-{seq}", 1);
        // c can't be renamed (the share went away), and neither can Trip-1 be moved back
        fs.fail.borrow_mut().extend(["c.jpg".to_string(), "Trip-1".to_string()]);
-        let err = s.apply_rename_with(&fs, &plans).unwrap_err().to_string();
+        let err = s.apply_rename_with(&fs, &plans).unwrap_err().to_string().replace('\\', "/");
        assert!(err.contains("rename /p/c.jpg"), "{err}");
        assert!(err.contains("/p/Trip-1.jpg could not be moved back"), "{err}");
        assert!(err.contains("/p/a.jpg → /p/Trip-1.jpg"), "lists what stayed renamed: {err}");
@@ -876,7 +956,7 @@ mod tests {
        );
        // the catalog matches the disk
        let path = |s: &Session, id: u64| match &s.catalog.photo(PhotoId(id)).unwrap().source {
-            Source::File { path } => path.clone(),
+            Source::File { path } => path.replace('\\', "/"),
            Source::Demo { .. } => String::new(),
        };
        assert_eq!(path(&s, 1), "/p/Trip-1.jpg");
@@ -890,7 +970,7 @@ mod tests {
        fs.fail.borrow_mut().extend(["d.jpg.xmp".to_string(), "/p/e.jpg".to_string()]);
        let e = move_file_with(&fs, "/p/d.jpg", "/p/e.jpg").unwrap_err();
        assert!(e.moved, "{e}");
-        assert!(e.message.contains("it is now /p/e.jpg with its sidecar /p/e.xmp"), "{e}");
+        assert!(e.message.replace('\\', "/").contains("it is now /p/e.jpg with its sidecar /p/e.xmp"), "{e}");
        assert_eq!(fs.listing(), vec![("/p/d.jpg.xmp".into(), "Df".into()), ("/p/e.jpg".into(), "D".into()), ("/p/e.xmp".into(), "Ds".into())]);
        // … and when the file does go back, its sidecars follow it
        let fs = FakeFs::new(false, &[("/p/d.jpg", "D"), ("/p/d.xmp", "Ds"), ("/p/d.jpg.xmp", "Df")]);
@@ -0,0 +1,146 @@
+//! The model download as a background task the session starts, watches and cancels without
+//! ever blocking: progress lives in atomics, messages behind a mutex only ever `try_lock`ed
+//! by the session (the download thread holds it for a few instructions at a time).
+
+use std::path::PathBuf;
+use std::sync::atomic::{AtomicBool, AtomicU64, Ordering};
+use std::sync::{Arc, Mutex};
+
+use lightcraft_segment::fetch::{self, Options, Progress};
+
+/// What the session sees of a download.
+#[derive(Clone, Debug, Default, PartialEq, Eq, serde::Serialize)]
+pub struct Status {
+    pub running: bool,
+    pub done: u64,
+    pub total: u64,
+    /// The file being fetched.
+    pub file: String,
+    /// The last download's error (cleared when a new one starts).
+    pub error: Option<String>,
+    /// The last download finished and the files are in place.
+    pub finished: bool,
+}
+
+#[derive(Default)]
+struct Text {
+    file: String,
+    error: Option<String>,
+}
+
+#[derive(Default)]
+struct Shared {
+    running: AtomicBool,
+    cancel: AtomicBool,
+    finished: AtomicBool,
+    done: AtomicU64,
+    total: AtomicU64,
+    text: Mutex<Text>,
+}
+
+/// Clears `running` when the download thread ends, however it ends.
+struct Running(Arc<Shared>);
+
+impl Drop for Running {
+    fn drop(&mut self) {
+        self.0.running.store(false, Ordering::SeqCst);
+    }
+}
+
+#[derive(Default)]
+pub struct Downloader {
+    shared: Arc<Shared>,
+    /// The last text seen (when the download thread held the lock at that moment).
+    last: Mutex<Text>,
+}
+
+fn lock(m: &Mutex<Text>) -> std::sync::MutexGuard<'_, Text> {
+    m.lock().unwrap_or_else(std::sync::PoisonError::into_inner)
+}
+
+impl Downloader {
+    pub fn status(&self) -> Status {
+        let s = &self.shared;
+        if let Ok(t) = s.text.try_lock()
+            && let Ok(mut last) = self.last.try_lock()
+        {
+            last.file.clone_from(&t.file);
+            last.error.clone_from(&t.error);
+        }
+        // (only the session's thread locks `last`)
+        let (file, error) = self.last.try_lock().map(|l| (l.file.clone(), l.error.clone())).unwrap_or_default();
+        Status {
+            running: s.running.load(Ordering::SeqCst),
+            done: s.done.load(Ordering::SeqCst),
+            total: s.total.load(Ordering::SeqCst),
+            file,
+            error,
+            finished: s.finished.load(Ordering::SeqCst),
+        }
+    }
+
+    pub fn running(&self) -> bool {
+        self.shared.running.load(Ordering::SeqCst)
+    }
+
+    /// Ask a running download to stop (it keeps its partial files to resume later).
+    pub fn cancel(&self) -> bool {
+        let running = self.running();
+        if running {
+            self.shared.cancel.store(true, Ordering::SeqCst);
+        }
+        running
+    }
+
+    /// Start downloading `files` from `mirrors` into `dir` on a background thread. False when
+    /// one is already running.
+    pub fn start(&self, files: &'static [fetch::FileSpec], mirrors: Vec<String>, dir: PathBuf, opts: Options) -> Result<bool, String> {
+        let s = self.shared.clone();
+        if s.running.swap(true, Ordering::SeqCst) {
+            return Ok(false);
+        }
+        s.cancel.store(false, Ordering::SeqCst);
+        s.finished.store(false, Ordering::SeqCst);
+        s.done.store(0, Ordering::SeqCst);
+        s.total.store(files.iter().filter_map(|f| f.size).sum(), Ordering::SeqCst);
+        // nothing else runs while `running` was false
+        *lock(&s.text) = Text::default();
+        *lock(&self.last) = Text::default();
+        let guard = Running(s.clone());
+        let spawned = std::thread::Builder::new().name("sam3-download".into()).spawn(move || {
+            let s = guard.0.clone();
+            let mut last_file = String::new();
+            let mut on_progress = |p: &Progress| {
+                s.done.store(p.done, Ordering::SeqCst);
+                s.total.store(p.total, Ordering::SeqCst);
+                if p.file != last_file {
+                    last_file.clone_from(&p.file);
+                    lock(&s.text).file.clone_from(&p.file);
+                }
+            };
+            let r =
+                std::panic::catch_unwind(std::panic::AssertUnwindSafe(|| fetch::download(files, &mirrors, &dir, &opts, &s.cancel, &mut on_progress)));
+            let error = match r {
+                Ok(Ok(())) => {
+                    s.finished.store(true, Ordering::SeqCst);
+                    log::info!("SAM 3 model downloaded to {}", dir.display());
+                    None
+                }
+                Ok(Err(e)) => Some(e.to_string()),
+                Err(_) => Some("the download failed unexpectedly".to_string()),
+            };
+            if let Some(e) = &error {
+                log::warn!("SAM 3 download: {e}");
+            }
+            lock(&s.text).error = error;
+            drop(guard);
+        });
+        match spawned {
+            Ok(_) => Ok(true),
+            Err(e) => {
+                // the closure (and its guard) was dropped: `running` is false again
+                Err(format!("could not start the download: {e}"))
+            }
+        }
+    }
+}
@@ -0,0 +1,715 @@
+//! AI masks: Object (clicks) and Describe (text) selections computed with SAM 3
+//! (`lightcraft-segment`, cargo feature `sam`; the desktop app enables it).
+//!
+//! **Nothing requires the model.** It is not part of LightCraft (SAM License); the user
+//! downloads it when they first use an AI mask and agree to (`segment.model.download`), or
+//! puts the files in the model folder themselves. Without it, AI mask requests fail with a
+//! clear "not installed" error; renders, exports and every other feature never touch it
+//! (stored segmentations are plain data in the develop settings).
+//!
+//! The model sees the photo as developed, uncropped and without masks, at 1008 px — the frame
+//! mask coordinates live in — so a stored segmentation lines up with the photo at any size.
+//! Everything that touches the model (loading it, rendering and encoding the photo, clicks,
+//! descriptions, detail passes) runs on one worker thread ([`worker`]); the session talks to it
+//! over channels and never waits on a lock. With [`Segmenter::background`] (the desktop app)
+//! commands return at once and [`Session::segment_poll`] applies the results; without it (CLI,
+//! MCP, tests) they wait for the worker.
+
+#[cfg(feature = "sam")]
+mod download;
+#[cfg(feature = "sam")]
+mod worker;
+
+use std::path::PathBuf;
+
+use lightcraft_catalog::PhotoId;
+use lightcraft_develop::{MaskShape, SegMask};
+use lightcraft_geom::Point;
+
+use crate::Session;
+
+/// Long edge of the image the model sees.
+pub const INPUT_EDGE: usize = 1008;
+/// Download size of the model (`model.safetensors`; the tokenizer files add ~2 MB).
+pub const MODEL_BYTES: u64 = 3_439_938_512;
+/// The model's licence (not LightCraft's): shown before downloading.
+pub const LICENSE_NAME: &str = "SAM License (Meta)";
+pub const LICENSE_URL: &str = "https://github.com/facebookresearch/sam3/blob/main/LICENSE";
+/// How errors about a missing model start (the UI offers the download on it).
+pub const NOT_INSTALLED: &str = "The SAM 3 model is not installed";
+/// Longest a waiting command (CLI, MCP) waits for the model (loading on a CPU can take minutes).
+#[cfg_attr(not(feature = "sam"), allow(dead_code))]
+const WAIT: std::time::Duration = std::time::Duration::from_secs(15 * 60);
+/// Most clicks one Object selection takes (the model's prompt grows with each).
+pub const MAX_CLICKS: usize = 64;
+
+/// One click of an Object selection (normalized image coordinates).
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub struct Click {
+    pub at: Point,
+    pub include: bool,
+}
+
+/// What a request's result is for (how [`Session::segment_poll`] applies it).
+#[derive(Clone, Debug, PartialEq)]
+#[cfg_attr(not(feature = "sam"), allow(dead_code))]
+pub(crate) enum Tag {
+    /// A command waiting for the result itself.
+    Wait,
+    /// Load the model and encode the photo ahead of the first click.
+    Prepare,
+    /// Object clicks on component `comp` of mask `mask`.
+    Clicks { photo: PhotoId, mask: u32, comp: usize, hint: Vec<Point>, exclude: Vec<Point> },
+    /// A Describe selection: a new mask (`mask: None`) or a component combined by `op`.
+    NewPrompt { photo: PhotoId, mask: Option<u32>, op: String, name: Option<String>, text: String },
+    /// A zoomed-in pass for a component, computed from `shape` (without its detail).
+    Detail { photo: PhotoId, mask: u32, comp: usize, shape: MaskShape },
+}
+
+/// The model input: 8-bit RGB.
+#[cfg_attr(not(feature = "sam"), allow(dead_code))]
+pub(crate) struct Input {
+    rgb: Vec<u8>,
+    w: usize,
+    h: usize,
+}
+
+/// What a detail pass re-runs.
+#[cfg_attr(not(feature = "sam"), allow(dead_code))]
+pub(crate) enum Prompt {
+    Clicks(Vec<Click>),
+    Text(String),
+}
+
+/// Object clicks sent to the worker and not applied yet (background mode): further clicks add
+/// to these, and the loupe shows them.
+#[derive(Clone, Debug, PartialEq)]
+pub struct PendingClicks {
+    pub photo: PhotoId,
+    pub mask: u32,
+    pub comp: usize,
+    pub hint: Vec<Point>,
+    pub exclude: Vec<Point>,
+}
+
+/// What [`Session::segment_poll`] did.
+#[derive(Debug, Default)]
+pub struct Polled {
+    /// A mask changed.
+    pub changed: bool,
+    /// Errors and notices from background work, for the user.
+    pub messages: Vec<String>,
+    /// A mask that got a new selection (worth a detail pass).
+    pub refine: Option<u32>,
+}
+
+/// The model download (`segment.model.*`).
+#[derive(Clone, Debug, Default, PartialEq, Eq, serde::Serialize)]
+pub struct DownloadStatus {
+    pub running: bool,
+    pub done: u64,
+    pub total: u64,
+    pub file: String,
+    pub error: Option<String>,
+    pub finished: bool,
+}
+
+/// The model (on its worker thread), the download, and AI mask requests in flight.
+pub struct Segmenter {
+    /// Where the `facebook/sam3` files live (set by the app; `None`: no AI masks).
+    pub dir: Option<PathBuf>,
+    /// The user's list of download mirrors (one base URL per line), if any.
+    pub mirrors_file: Option<PathBuf>,
+    /// Run requests in the background and apply them in [`Session::segment_poll`] (the
+    /// desktop app); otherwise commands wait for their result (CLI, MCP, tests).
+    pub background: bool,
+    pending: Option<PendingClicks>,
+    messages: Vec<String>,
+    #[cfg(feature = "sam")]
+    worker: worker::Worker,
+    #[cfg(feature = "sam")]
+    download: download::Downloader,
+    #[cfg(feature = "sam")]
+    results: (std::sync::mpsc::Sender<worker::Outcome>, std::sync::mpsc::Receiver<worker::Outcome>),
+}
+
+// (derivable only without the `sam` feature: the results channel has no Default)
+#[allow(clippy::derivable_impls)]
+impl Default for Segmenter {
+    fn default() -> Self {
+        Segmenter {
+            dir: None,
+            mirrors_file: None,
+            background: false,
+            pending: None,
+            messages: Vec::new(),
+            #[cfg(feature = "sam")]
+            worker: worker::Worker::default(),
+            #[cfg(feature = "sam")]
+            download: download::Downloader::default(),
+            #[cfg(feature = "sam")]
+            results: std::sync::mpsc::channel(),
+        }
+    }
+}
+
+impl Segmenter {
+    /// Whether this build can compute AI masks at all.
+    pub const AVAILABLE: bool = cfg!(feature = "sam");
+
+    /// Whether the model's files are in place.
+    pub fn installed(&self) -> bool {
+        #[cfg(feature = "sam")]
+        if let Some(dir) = &self.dir {
+            return lightcraft_segment::is_model_dir(dir);
+        }
+        false
+    }
+
+    /// Whether requests are queued or running (loading, analyzing the photo, a click…).
+    pub fn busy(&self) -> bool {
+        #[cfg(feature = "sam")]
+        return self.worker.pending() > 0;
+        #[cfg(not(feature = "sam"))]
+        false
+    }
+
+    /// Whether the slow part runs now: loading the model or analyzing a photo.
+    pub fn analyzing(&self) -> bool {
+        #[cfg(feature = "sam")]
+        return self.worker.encoding();
+        #[cfg(not(feature = "sam"))]
+        false
+    }
+
+    /// Whether a zoomed-in detail pass is queued or running.
+    pub fn detail_busy(&self) -> bool {
+        #[cfg(feature = "sam")]
+        return self.worker.detail() > 0;
+        #[cfg(not(feature = "sam"))]
+        false
+    }
+
+    /// Whether the model is in memory (it is unloaded after a while without use).
+    pub fn loaded(&self) -> bool {
+        #[cfg(feature = "sam")]
+        return self.worker.loaded();
+        #[cfg(not(feature = "sam"))]
+        false
+    }
+
+    /// Clicks waiting for their segmentation.
+    pub fn pending_clicks(&self) -> Option<&PendingClicks> {
+        self.pending.as_ref()
+    }
+
+    /// The model download's state.
+    pub fn download_status(&self) -> DownloadStatus {
+        #[cfg(feature = "sam")]
+        {
+            let s = self.download.status();
+            DownloadStatus { running: s.running, done: s.done, total: s.total, file: s.file, error: s.error, finished: s.finished }
+        }
+        #[cfg(not(feature = "sam"))]
+        DownloadStatus::default()
+    }
+
+    /// Where the model is downloaded from, in order (the user's mirrors first).
+    pub fn mirrors(&self) -> Vec<String> {
+        #[cfg(feature = "sam")]
+        {
+            let env = std::env::var(lightcraft_segment::fetch::MIRRORS_ENV).ok();
+            lightcraft_segment::fetch::mirrors(env.as_deref(), self.mirrors_file.as_deref())
+        }
+        #[cfg(not(feature = "sam"))]
+        Vec::new()
+    }
+
+    /// The model folder, if the model is there; otherwise an error that says what to do.
+    pub fn model_dir(&self) -> Result<PathBuf, String> {
+        if !Self::AVAILABLE {
+            return Err("AI masks are not available in this build".into());
+        }
+        let dir = self.dir.clone().ok_or("no folder is set for the SAM 3 model")?;
+        if self.installed() {
+            return Ok(dir);
+        }
+        let d = self.download_status();
+        if d.running {
+            let pct = d.done.saturating_mul(100).checked_div(d.total).unwrap_or(0);
+            return Err(format!("{NOT_INSTALLED} yet: it is downloading ({pct} %)."));
+        }
+        Err(format!(
+            "{NOT_INSTALLED}. Download it (about {:.1} GB, {LICENSE_NAME}) when LightCraft offers it, with `segment.model.download {{\"acknowledged\": true}}`, or put model.safetensors, vocab.json and merges.txt in {}.",
+            MODEL_BYTES as f64 / 1e9,
+            dir.display()
+        ))
+    }
+
+    /// Start downloading the model (on a background thread; see `segment.model.download`).
+    /// `Ok(false)` when it is installed or downloading already.
+    pub fn start_download(&self) -> Result<bool, String> {
+        if !Self::AVAILABLE {
+            return Err("AI masks are not available in this build".into());
+        }
+        let dir = self.dir.clone().ok_or("no folder is set for the SAM 3 model")?;
+        if self.installed() {
+            return Ok(false);
+        }
+        #[cfg(feature = "sam")]
+        {
+            let mirrors = self.mirrors();
+            if mirrors.is_empty() {
+                return Err(lightcraft_segment::fetch::no_mirrors_message());
+            }
+            self.download.start(lightcraft_segment::fetch::SAM3_FILES, mirrors, dir, lightcraft_segment::fetch::options())
+        }
+        #[cfg(not(feature = "sam"))]
+        {
+            let _ = dir;
+            Ok(false)
+        }
+    }
+
+    /// Stop a running download (its partial files stay, to resume). False when none runs.
+    pub fn cancel_download(&self) -> bool {
+        #[cfg(feature = "sam")]
+        return self.download.cancel();
+        #[cfg(not(feature = "sam"))]
+        false
+    }
+}
+
+/// Mix `v` into a 64-bit hash.
+#[cfg_attr(not(feature = "sam"), allow(dead_code))]
+fn mix(h: u64, v: u64) -> u64 {
+    (h ^ v).wrapping_mul(0x0100_0000_01b3).rotate_left(29)
+}
+
+/// Objects covering more than this much of the photo gain little from a zoomed pass.
+const DETAIL_MAX_AREA: f64 = 0.4;
+
+/// The part of the photo to zoom into for `seg`'s selection: its bounding box with a margin of
+/// a quarter of its size, at least 12 % of the long edge, at most 2:1, inside the photo
+/// (`aspect` = width / height). `None` when nothing is selected or it is most of the photo.
+pub fn detail_region(seg: &SegMask, aspect: f64) -> Option<[f64; 4]> {
+    let logits = seg.logits()?;
+    let r = seg.bounds()?;
+    let side = seg.side as usize;
+    let (mut x0, mut y0, mut x1, mut y1) = (usize::MAX, usize::MAX, 0, 0);
+    for (i, l) in logits.iter().enumerate() {
+        if *l > 0.0 {
+            let (x, y) = (i % side, i / side);
+            (x0, y0, x1, y1) = (x0.min(x), y0.min(y), x1.max(x + 1), y1.max(y + 1));
+        }
+    }
+    if x0 == usize::MAX {
+        return None;
+    }
+    let (rw, rh) = (r[2] - r[0], r[3] - r[1]);
+    let nx = |c: usize| r[0] + c as f64 / side as f64 * rw;
+    let ny = |c: usize| r[1] + c as f64 / side as f64 * rh;
+    let (bx0, by0, bx1, by1) = (nx(x0), ny(y0), nx(x1), ny(y1));
+    if (bx1 - bx0) * (by1 - by0) > DETAIL_MAX_AREA {
+        return None;
+    }
+    // in units of the photo's height: x × aspect
+    let a = if aspect.is_finite() { aspect.clamp(0.1, 10.0) } else { 1.0 };
+    let (cx, cy) = ((bx0 + bx1) / 2.0 * a, (by0 + by1) / 2.0);
+    let size = ((bx1 - bx0) * a).max(by1 - by0);
+    let m = 0.25 * size;
+    let mut w = ((bx1 - bx0) * a + 2.0 * m).max(0.12 * a.max(1.0));
+    let mut h = ((by1 - by0) + 2.0 * m).max(0.12 * a.max(1.0));
+    w = w.max(h / 2.0).min(a);
+    h = h.max(w / 2.0).min(1.0);
+    let x = (cx - w / 2.0).clamp(0.0, (a - w).max(0.0));
+    let y = (cy - h / 2.0).clamp(0.0, (1.0 - h).max(0.0));
+    let out = [x / a, y, (x + w) / a, y + h];
+    // a region nearly the whole photo isn't worth a second pass
+    ((out[2] - out[0]) * (out[3] - out[1]) < 0.8).then_some(out)
+}
+
+/// `shape` without its detail patches (what a detail pass was computed from)
+#[cfg_attr(not(feature = "sam"), allow(dead_code))]
+fn strip_detail(mut shape: MaskShape) -> MaskShape {
+    // (nor its edge setting: moving the slider meanwhile keeps the pass)
+    if let MaskShape::Object { detail, edge, .. } | MaskShape::Prompt { detail, edge, .. } = &mut shape {
+        detail.clear();
+        *edge = 0.0;
+    }
+    shape
+}
+
+fn clicks_of(include: &[Point], exclude: &[Point]) -> Vec<Click> {
+    include.iter().map(|p| Click { at: *p, include: true }).chain(exclude.iter().map(|p| Click { at: *p, include: false })).collect()
+}
+
+impl Session {
+    /// The key and settings of photo `id` as the model sees it: its look without masks, uncropped.
+    #[cfg_attr(not(feature = "sam"), allow(dead_code))]
+    fn segment_key(&self, id: PhotoId) -> Option<(u64, lightcraft_develop::DevelopSettings)> {
+        let p = self.catalog.photo(id)?;
+        let mut d = (*p.develop).clone();
+        d.masks.clear();
+        let content = crate::media::content_key(p);
+        let mut h = mix(0xcbf2_9ce4_8422_2325, d.hash64());
+        h = mix(h, id.0);
+        for b in content.bytes() {
+            h = mix(h, u64::from(b));
+        }
+        Some((h, d))
+    }
+
+    /// Clicks (in normalized photo coordinates) for the model.
+    #[cfg(feature = "sam")]
+    fn model_clicks(clicks: &[Click]) -> Vec<lightcraft_segment::Click> {
+        clicks.iter().map(|c| lightcraft_segment::Click { x: c.at.x as f32, y: c.at.y as f32, positive: c.include }).collect()
+    }
+
+    /// A worker request about photo `id` (the render job for its model input goes along; the
+    /// worker runs it only when its cache doesn't hold the photo). `region` renders that part
+    /// of the photo, from a source sharp enough for it (detail passes).
+    #[cfg(feature = "sam")]
+    fn segment_job(
+        &mut self,
+        id: PhotoId,
+        kind: worker::Kind,
+        tag: Tag,
+        reply: std::sync::mpsc::Sender<worker::Outcome>,
+        region: Option<[f64; 4]>,
+    ) -> Result<worker::Job, String> {
+        let dir = self.segmenter.model_dir()?;
+        let (key, mut d) = self.segment_key(id).ok_or("no such photo")?;
+        let p = self.catalog.photo(id).ok_or("no such photo")?.clone();
+        let missing = match &p.source {
+            lightcraft_catalog::Source::File { path } if !std::path::Path::new(path).exists() => Some(path.clone()),
+            _ => None,
+        };
+        let render = match region {
+            None => self.preview_job(id, INPUT_EDGE, INPUT_EDGE, false, &d).ok_or("no such photo")?,
+            Some(region) => {
+                d.crop.geometry =
+                    lightcraft_geom::CropGeometry { rect: lightcraft_geom::Rect::new(region[0], region[1], region[2], region[3]), angle: 0.0 };
+                d.crop.flip_h = false;
+                d.crop.flip_v = false;
+                d.geometry.constrain_crop = false;
+                let mut job = self.preview_job(id, INPUT_EDGE, INPUT_EDGE, true, &d).ok_or("no such photo")?;
+                let frac = (region[2] - region[0]).max(region[3] - region[1]).max(0.01);
+                job.level = crate::media::SourceLevel::for_size((INPUT_EDGE as f64 / frac) as usize);
+                job.source = self.media.source_ref(&p, job.level);
+                job
+            }
+        };
+        Ok(worker::Job { dir, key: if region.is_some() { 0 } else { key }, render: Some(render), missing, kind, tag, reply })
+    }
+
+    /// Send a request and wait for its result (CLI, MCP, tests; or when not in background mode).
+    #[cfg(feature = "sam")]
+    fn segment_wait(&mut self, id: PhotoId, kind: worker::Kind, region: Option<[f64; 4]>) -> Result<Option<SegMask>, String> {
+        let (tx, rx) = std::sync::mpsc::channel();
+        let job = self.segment_job(id, kind, Tag::Wait, tx, region)?;
+        self.segmenter.worker.submit(job)?;
+        match rx.recv_timeout(WAIT) {
+            Ok(o) => o.result,
+            Err(_) => Err("the AI model took too long; try again".into()),
+        }
+    }
+
+    /// Send a request whose result [`Session::segment_poll`] applies.
+    #[cfg(feature = "sam")]
+    fn segment_queue(&mut self, id: PhotoId, kind: worker::Kind, tag: Tag, region: Option<[f64; 4]>) -> Result<(), String> {
+        let reply = self.segmenter.results.0.clone();
+        let job = self.segment_job(id, kind, tag, reply, region)?;
+        self.segmenter.worker.submit(job)
+    }
+
+    /// Start preparing photo `id` for AI masks (load the model, encode the image), so the first
+    /// click is fast. In background mode it returns at once.
+    pub fn segment_prepare(&mut self, id: PhotoId) -> Result<(), String> {
+        self.segmenter.model_dir()?;
+        #[cfg(feature = "sam")]
+        {
+            if self.segmenter.background {
+                return self.segment_queue(id, worker::Kind::Prepare, Tag::Prepare, None);
+            }
+            self.segment_wait(id, worker::Kind::Prepare, None)?;
+        }
+        #[cfg(not(feature = "sam"))]
+        let _ = id;
+        Ok(())
+    }
+
+    /// Segment the object `clicks` pick on photo `id`, waiting for the model.
+    pub fn segment_clicks(&mut self, id: PhotoId, clicks: &[Click]) -> Result<SegMask, String> {
+        self.segmenter.model_dir()?;
+        if !clicks.iter().any(|c| c.include) {
+            return Err("click the object to include it first".into());
+        }
+        #[cfg(feature = "sam")]
+        {
+            self.segment_wait(id, worker::Kind::Clicks(Self::model_clicks(clicks)), None)?.ok_or_else(|| "nothing was selected".to_string())
+        }
+        #[cfg(not(feature = "sam"))]
+        {
+            let _ = id;
+            Err("AI masks are not available in this build".into())
+        }
+    }
+
+    /// Segment everything `text` describes on photo `id`, waiting for the model; `Ok(None)`
+    /// when nothing matches.
+    pub fn segment_text(&mut self, id: PhotoId, text: &str) -> Result<Option<SegMask>, String> {
+        self.segmenter.model_dir()?;
+        let text = text.trim();
+        if text.is_empty() {
+            return Err("describe what to select".into());
+        }
+        #[cfg(feature = "sam")]
+        {
+            self.segment_wait(id, worker::Kind::Text(text.to_string()), None)
+        }
+        #[cfg(not(feature = "sam"))]
+        {
+            let _ = id;
+            Err("AI masks are not available in this build".into())
+        }
+    }
+
+    /// Background mode: queue Object clicks for component `comp` of mask `mask`; the result
+    /// (clicks and segmentation, one undo step) is applied by [`Session::segment_poll`].
+    pub(crate) fn segment_clicks_later(&mut self, id: PhotoId, mask: u32, comp: usize, hint: Vec<Point>, exclude: Vec<Point>) -> Result<(), String> {
+        self.segmenter.model_dir()?;
+        if hint.is_empty() {
+            return Err("click the object to include it first".into());
+        }
+        #[cfg(feature = "sam")]
+        {
+            let clicks = Self::model_clicks(&clicks_of(&hint, &exclude));
+            let tag = Tag::Clicks { photo: id, mask, comp, hint: hint.clone(), exclude: exclude.clone() };
+            self.segment_queue(id, worker::Kind::Clicks(clicks), tag, None)?;
+            self.segmenter.pending = Some(PendingClicks { photo: id, mask, comp, hint, exclude });
+            Ok(())
+        }
+        #[cfg(not(feature = "sam"))]
+        {
+            let _ = (id, mask, comp, exclude);
+            Err("AI masks are not available in this build".into())
+        }
+    }
+
+    /// Background mode: queue a Describe selection; the mask (or component, combined by `op`
+    /// into mask `mask`) is created by [`Session::segment_poll`] when something matches.
+    pub(crate) fn segment_text_later(&mut self, id: PhotoId, mask: Option<u32>, op: &str, name: Option<String>, text: &str) -> Result<(), String> {
+        self.segmenter.model_dir()?;
+        let text = text.trim();
+        if text.is_empty() {
+            return Err("describe what to select".into());
+        }
+        #[cfg(feature = "sam")]
+        {
+            let tag = Tag::NewPrompt { photo: id, mask, op: op.to_string(), name, text: text.to_string() };
+            self.segment_queue(id, worker::Kind::Text(text.to_string()), tag, None)
+        }
+        #[cfg(not(feature = "sam"))]
+        {
+            let _ = (id, mask, op, name);
+            Err("AI masks are not available in this build".into())
+        }
+    }
+
+    /// Start a zoomed-in pass for component `comp` of mask `mask` on photo `id` (an Object or
+    /// Describe selection): the photo around the selection is rendered at a higher resolution
+    /// and segmented again. In background mode [`Session::segment_poll`] applies the result;
+    /// otherwise it is applied before this returns. `Ok(false)` when there is nothing to
+    /// refine (no selection yet, or it is most of the photo) or a pass is running already.
+    pub fn segment_detail(&mut self, id: PhotoId, mask: u32, comp: usize) -> Result<bool, String> {
+        self.segmenter.model_dir()?;
+        let d = self.develop_of(id).ok_or("no such photo")?;
+        let shape = d.masks.iter().find(|m| m.id == mask).and_then(|m| m.components.get(comp)).map(|c| c.shape.clone()).ok_or("no such mask")?;
+        let (seg, prompt) = match &shape {
+            // (a document with absurdly many clicks isn't run through the model)
+            MaskShape::Object { hint, exclude, seg: Some(seg), .. } if !hint.is_empty() && hint.len() + exclude.len() <= MAX_CLICKS => {
+                (seg.clone(), Prompt::Clicks(clicks_of(hint, exclude)))
+            }
+            MaskShape::Prompt { text, seg: Some(seg), .. } => (seg.clone(), Prompt::Text(text.clone())),
+            _ => return Ok(false),
+        };
+        let p = self.catalog.photo(id).ok_or("no such photo")?;
+        let (pw, ph) = (f64::from(p.width.max(1)), f64::from(p.height.max(1)));
+        let aspect = if d.orientation.swaps_axes() { ph / pw } else { pw / ph };
+        let Some(region) = detail_region(&seg, aspect) else { return Ok(false) };
+        #[cfg(feature = "sam")]
+        {
+            let kind = worker::Kind::Detail { prompt, region };
+            let tag = Tag::Detail { photo: id, mask, comp, shape: strip_detail(shape) };
+            if self.segmenter.background {
+                if self.segmenter.detail_busy() {
+                    return Ok(false);
+                }
+                self.segment_queue(id, kind, tag, Some(region))?;
+            } else {
+                let patch = self.segment_wait(id, kind, Some(region))?;
+                let outcome = worker::Outcome { tag, result: Ok(patch), superseded: false };
+                let mut polled = Polled::default();
+                self.apply_outcome(outcome, &mut polled);
+            }
+            Ok(true)
+        }
+        #[cfg(not(feature = "sam"))]
+        {
+            let _ = (prompt, region, mask);
+            Ok(false)
+        }
+    }
+
+    /// Apply finished background requests (to masks that haven't changed since) and collect
+    /// their messages. Cheap when nothing is pending: call it every frame.
+    pub fn segment_poll(&mut self) -> Polled {
+        #[cfg_attr(not(feature = "sam"), allow(unused_mut))]
+        let mut polled = Polled { messages: std::mem::take(&mut self.segmenter.messages), ..Default::default() };
+        #[cfg(feature = "sam")]
+        {
+            // (before draining: a worker that is idle now has sent everything)
+            let idle = !self.segmenter.busy();
+            let done: Vec<worker::Outcome> = self.segmenter.results.1.try_iter().collect();
+            for o in done {
+                self.apply_outcome(o, &mut polled);
+            }
+            // clicks whose request was lost (the worker restarted) aren't pending forever
+            if idle {
+                self.segmenter.pending = None;
+            }
+        }
+        polled
+    }
+
+    #[cfg(feature = "sam")]
+    fn apply_outcome(&mut self, o: worker::Outcome, polled: &mut Polled) {
+        if o.superseded {
+            return;
+        }
+        match o.tag {
+            Tag::Wait => {}
+            Tag::Prepare => {
+                if let Err(e) = o.result {
+                    polled.messages.push(e);
+                }
+            }
+            Tag::Clicks { photo, mask, comp, hint, exclude } => {
+                let latest = PendingClicks { photo, mask, comp, hint, exclude };
+                if self.segmenter.pending.as_ref() != Some(&latest) {
+                    return; // newer clicks are on their way
+                }
+                self.segmenter.pending = None;
+                let seg = match o.result {
+                    Ok(Some(seg)) => seg,
+                    Ok(None) => return,
+                    Err(e) => return polled.messages.push(e),
+                };
+                let Some(d) = self.develop_of(photo) else { return };
+                let mut d = (*d).clone();
+                let Some(c) = d.masks.iter_mut().find(|m| m.id == mask).and_then(|m| m.components.get_mut(comp)) else { return };
+                let MaskShape::Object { edge, .. } = c.shape else { return };
+                c.shape = MaskShape::Object { hint: latest.hint, exclude: latest.exclude, seg: Some(seg), detail: vec![], edge };
+                match self.set_develop(photo, d, "Object Mask") {
+                    Ok(()) => {
+                        polled.changed = true;
+                        polled.refine = Some(mask);
+                    }
+                    Err(e) => polled.messages.push(e.to_string()),
+                }
+            }
+            Tag::NewPrompt { photo, mask, op, name, text } => {
+                let seg = match o.result {
+                    Ok(Some(seg)) => seg,
+                    Ok(None) => return polled.messages.push(format!("Nothing matching “{text}” was found in this photo.")),
+                    Err(e) => return polled.messages.push(e),
+                };
+                if self.active() != Some(photo) {
+                    return polled.messages.push(format!("The photo changed before “{text}” was found; try again."));
+                }
+                let Ok(seg) = serde_json::to_value(seg) else { return };
+                let mut p = serde_json::json!({"kind": "prompt", "text": text, "seg": seg});
+                if let Some(n) = name {
+                    p["name"] = serde_json::json!(n);
+                }
+                let r = match mask {
+                    None => self.execute("mask.add", &p),
+                    Some(m) => {
+                        if !self.develop_of(photo).is_some_and(|d| d.masks.iter().any(|x| x.id == m)) {
+                            return polled.messages.push("The mask was removed before the selection was found.".into());
+                        }
+                        self.active_mask = Some(m);
+                        p["op"] = serde_json::json!(op);
+                        self.execute("mask.addComponent", &p)
+                    }
+                };
+                match r {
+                    Ok(_) => {
+                        polled.changed = true;
+                        polled.refine = self.active_mask;
+                    }
+                    Err(e) => polled.messages.push(e.to_string()),
+                }
+            }
+            Tag::Detail { photo, mask, comp, shape } => {
+                let patch = match o.result {
+                    Ok(Some(p)) => p,
+                    Ok(None) => return,
+                    Err(e) => return log::warn!("SAM 3 detail pass: {e}"),
+                };
+                let Some(d) = self.develop_of(photo) else { return };
+                let mut d = (*d).clone();
+                let Some(c) = d.masks.iter_mut().find(|m| m.id == mask).and_then(|m| m.components.get_mut(comp)) else { return };
+                if strip_detail(c.shape.clone()) != shape {
+                    return; // clicked again meanwhile: a newer pass will follow
+                }
+                match &mut c.shape {
+                    MaskShape::Object { detail, .. } | MaskShape::Prompt { detail, .. } => *detail = vec![patch],
+                    _ => return,
+                }
+                match self.set_develop(photo, d, "AI Mask Detail") {
+                    Ok(()) => polled.changed = true,
+                    Err(e) => log::warn!("AI mask detail: {e}"),
+                }
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn seg_box(side: usize, x0: usize, y0: usize, x1: usize, y1: usize) -> SegMask {
+        let l: Vec<f32> =
+            (0..side * side).map(|i| if (x0..x1).contains(&(i % side)) && (y0..y1).contains(&(i / side)) { 8.0 } else { -8.0 }).collect();
+        SegMask::from_logits(side, &l)
+    }
+
+    #[test]
+    fn detail_region_frames_the_selection_with_a_margin() {
+        // a small object in the middle of a square photo
+        let r = detail_region(&seg_box(100, 40, 45, 50, 55), 1.0).unwrap();
+        assert!(r[0] < 0.4 && r[2] > 0.5 && r[1] < 0.45 && r[3] > 0.55, "contains it: {r:?}");
+        assert!(r[2] - r[0] < 0.25 && r[3] - r[1] < 0.25, "zoomed in: {r:?}");
+        assert!(r.iter().all(|v| (0.0..=1.0).contains(v)));
+        // at the corner: shifted inside the photo, not cut
+        let r = detail_region(&seg_box(100, 0, 0, 5, 5), 1.5).unwrap();
+        assert!(r[0] >= 0.0 && r[1] >= 0.0 && r[0] < 1e-9 && r[1] < 1e-9);
+        // a thin object stays at most 2:1 (in photo pixels, 1.5:1 photo)
+        let r = detail_region(&seg_box(100, 10, 50, 90, 52), 1.5).unwrap();
+        let (w, h) = ((r[2] - r[0]) * 1.5, r[3] - r[1]);
+        assert!(w / h <= 2.0 + 1e-9, "{w} × {h}");
+        // a hostile aspect ratio stays sane
+        assert!(detail_region(&seg_box(100, 40, 45, 50, 55), f64::NAN).is_some_and(|r| r.iter().all(|v| v.is_finite())));
+    }
+
+    #[test]
+    fn no_region_for_nothing_or_most_of_the_photo() {
+        assert!(detail_region(&seg_box(50, 0, 0, 0, 0), 1.0).is_none());
+        assert!(detail_region(&seg_box(50, 2, 2, 48, 48), 1.0).is_none());
+        let damaged = SegMask { side: 50, data: "?".into(), rect: None };
+        assert!(detail_region(&damaged, 1.0).is_none());
+    }
+}
@@ -0,0 +1,430 @@
+//! The SAM 3 worker thread: it owns the model and the last encoded photo, and runs every
+//! request (load, render the model input, encode, clicks, descriptions, detail passes) in
+//! turn. The session only sends jobs and receives outcomes over channels, so no thread ever
+//! waits on a lock the model holds, and the UI thread never runs the model.
+//!
+//! Every job runs under `catch_unwind`: a panic inside candle becomes an error outcome, drops
+//! the (possibly inconsistent) model and leaves the worker ready for the next job. The busy
+//! counters are decremented by drop guards, so they can't stay stuck. The model is unloaded
+//! after [`IDLE_UNLOAD`] without requests (it holds several GB).
+
+use std::collections::VecDeque;
+use std::panic::AssertUnwindSafe;
+use std::path::PathBuf;
+use std::sync::Arc;
+use std::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
+use std::sync::mpsc::{self, RecvTimeoutError};
+use std::time::Duration;
+
+use lightcraft_develop::SegMask;
+use lightcraft_segment::{Encoded, Sam3};
+
+use super::{Input, Prompt, Tag};
+use crate::media::RenderJob;
+
+/// Unload the model after this long without a request.
+pub const IDLE_UNLOAD: Duration = Duration::from_secs(10 * 60);
+
+/// What to compute.
+pub enum Kind {
+    /// Load the model and encode the photo (so the first click is fast).
+    Prepare,
+    Clicks(Vec<lightcraft_segment::Click>),
+    Text(String),
+    /// A zoomed-in pass over `region` (normalized) of the photo, rendered by the job's `render`.
+    Detail {
+        prompt: Prompt,
+        region: [f64; 4],
+    },
+    /// Panics (tests of the worker's recovery).
+    #[cfg(test)]
+    Panic,
+}
+
+/// One request.
+pub struct Job {
+    /// The model folder.
+    pub dir: PathBuf,
+    /// Which photo and look the request is about (the encode cache's key).
+    pub key: u64,
+    /// Renders the model input when the cache doesn't hold `key` (always for a detail pass).
+    pub render: Option<RenderJob>,
+    /// The photo's file, when it is missing on disk (for a clearer error if rendering fails).
+    pub missing: Option<String>,
+    pub kind: Kind,
+    pub tag: Tag,
+    pub reply: mpsc::Sender<Outcome>,
+}
+
+/// A finished request: the segmentation (`None`: nothing selected / nothing to report).
+pub struct Outcome {
+    pub tag: Tag,
+    pub result: Result<Option<SegMask>, String>,
+    /// A newer request for the same selection came in; this one was skipped.
+    pub superseded: bool,
+}
+
+/// Counters the session reads without locking.
+#[derive(Default)]
+pub struct Shared {
+    /// Requests other than detail passes, queued or running.
+    pub pending: AtomicUsize,
+    /// Detail passes queued or running.
+    pub detail: AtomicUsize,
+    /// The model is in memory.
+    pub loaded: AtomicBool,
+    /// Loading the model or encoding a photo right now (the slow parts).
+    pub encoding: AtomicBool,
+}
+
+/// Decrements a counter when dropped (also when unwinding).
+struct Done<'a>(&'a AtomicUsize);
+
+impl Drop for Done<'_> {
+    fn drop(&mut self) {
+        let _ = self.0.try_update(Ordering::SeqCst, Ordering::SeqCst, |n| Some(n.saturating_sub(1)));
+    }
+}
+
+/// Sets a flag while alive.
+struct Flag<'a>(&'a AtomicBool);
+
+impl<'a> Flag<'a> {
+    fn raise(f: &'a AtomicBool) -> Self {
+        f.store(true, Ordering::SeqCst);
+        Flag(f)
+    }
+}
+
+impl Drop for Flag<'_> {
+    fn drop(&mut self) {
+        self.0.store(false, Ordering::SeqCst);
+    }
+}
+
+/// The session's handle on the worker thread (started on the first request, restarted if it
+/// ever ends).
+#[derive(Default)]
+pub struct Worker {
+    tx: Option<mpsc::Sender<Job>>,
+    thread: Option<std::thread::JoinHandle<()>>,
+    pub shared: Arc<Shared>,
+}
+
+impl Worker {
+    fn counter(&self, job: &Job) -> &AtomicUsize {
+        if matches!(job.kind, Kind::Detail { .. }) { &self.shared.detail } else { &self.shared.pending }
+    }
+
+    /// Whether the thread has ended (it never should); its counters are then meaningless.
+    fn dead(&self) -> bool {
+        self.thread.as_ref().is_some_and(|t| t.is_finished())
+    }
+
+    pub fn pending(&self) -> usize {
+        if self.dead() { 0 } else { self.shared.pending.load(Ordering::SeqCst) }
+    }
+
+    pub fn detail(&self) -> usize {
+        if self.dead() { 0 } else { self.shared.detail.load(Ordering::SeqCst) }
+    }
+
+    pub fn encoding(&self) -> bool {
+        !self.dead() && self.shared.encoding.load(Ordering::SeqCst)
+    }
+
+    pub fn loaded(&self) -> bool {
+        !self.dead() && self.shared.loaded.load(Ordering::SeqCst)
+    }
+
+    /// Queue `job`; returns at once.
+    pub fn submit(&mut self, job: Job) -> Result<(), String> {
+        if self.dead() {
+            // a thread that ended took its counters' meaning with it
+            self.tx = None;
+            self.thread = None;
+            self.shared = Arc::new(Shared::default());
+        }
+        self.counter(&job).fetch_add(1, Ordering::SeqCst);
+        let job = match &self.tx {
+            Some(tx) => match tx.send(job) {
+                Ok(()) => return Ok(()),
+                Err(mpsc::SendError(job)) => job,
+            },
+            None => job,
+        };
+        // (re)start the thread
+        let (tx, rx) = mpsc::channel();
+        let shared = self.shared.clone();
+        match std::thread::Builder::new().name("sam3".into()).spawn(move || run(&rx, &shared, IDLE_UNLOAD)) {
+            Ok(t) => {
+                self.thread = Some(t);
+                self.tx = Some(tx.clone());
+                tx.send(job).map_err(|_| "the AI mask worker stopped".to_string())
+            }
+            Err(e) => {
+                let _ = self.counter(&job).try_update(Ordering::SeqCst, Ordering::SeqCst, |n| Some(n.saturating_sub(1)));
+                Err(format!("could not start the AI mask worker: {e}"))
+            }
+        }
+    }
+}
+
+/// The model and the last encoded photo.
+#[derive(Default)]
+struct State {
+    model: Option<(PathBuf, Sam3)>,
+    cache: Option<(u64, Encoded)>,
+}
+
+/// Whether `later` makes `job` pointless (it asks for the same selection again).
+fn supersedes(later: &Job, job: &Job) -> bool {
+    match (&later.tag, &job.tag) {
+        (Tag::Prepare, Tag::Prepare) => later.key == job.key,
+        (Tag::Clicks { photo: a, mask: am, comp: ac, .. }, Tag::Clicks { photo: b, mask: bm, comp: bc, .. }) => (a, am, ac) == (b, bm, bc),
+        (Tag::Detail { photo: a, mask: am, comp: ac, .. }, Tag::Detail { photo: b, mask: bm, comp: bc, .. }) => (a, am, ac) == (b, bm, bc),
+        _ => false,
+    }
+}
+
+fn run(rx: &mpsc::Receiver<Job>, shared: &Shared, idle: Duration) {
+    let mut state = State::default();
+    let mut queue: VecDeque<Job> = VecDeque::new();
+    loop {
+        if queue.is_empty() {
+            match rx.recv_timeout(idle) {
+                Ok(j) => queue.push_back(j),
+                Err(RecvTimeoutError::Timeout) => {
+                    if state.model.is_some() {
+                        state = State::default();
+                        shared.loaded.store(false, Ordering::SeqCst);
+                        log::info!("SAM 3 unloaded after {} minutes without use", idle.as_secs() / 60);
+                    }
+                    continue;
+                }
+                Err(RecvTimeoutError::Disconnected) => return,
+            }
+        }
+        while let Ok(j) = rx.try_recv() {
+            queue.push_back(j);
+        }
+        let Some(mut job) = queue.pop_front() else { continue };
+        let is_detail = matches!(job.kind, Kind::Detail { .. });
+        // counts the job as pending until just before its reply goes out: a caller woken by the
+        // reply must not still see the worker busy with it
+        let done = Done(if is_detail { &shared.detail } else { &shared.pending });
+        if queue.iter().any(|later| supersedes(later, &job)) {
+            drop(done);
+            let _ = job.reply.send(Outcome { tag: job.tag, result: Ok(None), superseded: true });
+            continue;
+        }
+        let result = match std::panic::catch_unwind(AssertUnwindSafe(|| run_job(&mut state, shared, &mut job))) {
+            Ok(r) => r,
+            Err(p) => {
+                let why = p.downcast_ref::<&str>().map(|s| s.to_string()).or_else(|| p.downcast_ref::<String>().cloned()).unwrap_or_default();
+                log::error!("SAM 3 panicked: {why}");
+                // don't trust what the model kept: load it again next time
+                state = State::default();
+                Err("the AI model failed unexpectedly (it will be reloaded on the next try)".to_string())
+            }
+        };
+        if result.is_err() && !is_detail {
+            state.cache = None;
+        }
+        shared.loaded.store(state.model.is_some(), Ordering::SeqCst);
+        drop(done);
+        let _ = job.reply.send(Outcome { tag: job.tag, result, superseded: false });
+    }
+}
+
+/// The model for `dir`, loading it when needed.
+fn model<'a>(state: &'a mut State, shared: &Shared, dir: &std::path::Path) -> Result<&'a mut Sam3, String> {
+    if state.model.as_ref().is_none_or(|(d, _)| d != dir) {
+        state.model = None;
+        state.cache = None;
+        let _busy = Flag::raise(&shared.encoding);
+        let t = web_time::Instant::now();
+        let m = Sam3::load(dir).map_err(|e| e.to_string())?;
+        log::info!("SAM 3 loaded in {:?}", t.elapsed());
+        state.model = Some((dir.to_path_buf(), m));
+        shared.loaded.store(true, Ordering::SeqCst);
+    }
+    state.model.as_mut().map(|(_, m)| m).ok_or_else(|| "the model did not load".to_string())
+}
+
+/// Render the model input.
+fn render(job: &mut Job) -> Result<Input, String> {
+    let r = job.render.take().ok_or("the photo is not available")?.run();
+    let img = match r.rendered {
+        Ok(r) => r.image,
+        Err(e) => {
+            return Err(match &job.missing {
+                Some(path) => format!(
+                    "This photo's file is missing (moved or deleted), so it can't be analyzed for AI masks: {path}. Library ▸ Find Missing Photos can relink it."
+                ),
+                None => format!("couldn't render the photo for AI masks: {e}"),
+            });
+        }
+    };
+    let rgb = img.data.iter().flat_map(|p| [p[0], p[1], p[2]]).collect();
+    Ok(Input { rgb, w: img.width, h: img.height })
+}
+
+/// The model and the encoded photo `job.key` (rendering and encoding it when needed).
+fn encoded<'a>(state: &'a mut State, shared: &Shared, job: &mut Job) -> Result<(&'a mut Sam3, &'a mut Encoded), String> {
+    model(state, shared, &job.dir)?;
+    if state.cache.as_ref().is_none_or(|(k, _)| *k != job.key) {
+        state.cache = None;
+        let input = render(job)?;
+        let _busy = Flag::raise(&shared.encoding);
+        let m = state.model.as_mut().map(|(_, m)| m).ok_or("the model did not load")?;
+        let t = web_time::Instant::now();
+        let mut enc = m.encode(&input.rgb, input.w, input.h).map_err(|e| e.to_string())?;
+        m.prepare_clicks(&mut enc).map_err(|e| e.to_string())?;
+        log::info!("SAM 3 encoded {}×{} in {:?}", input.w, input.h, t.elapsed());
+        state.cache = Some((job.key, enc));
+    }
+    let State { model, cache } = state;
+    match (model.as_mut(), cache.as_mut()) {
+        (Some((_, m)), Some((_, e))) => Ok((m, e)),
+        _ => Err("the model is not ready".into()),
+    }
+}
+
+/// Every phrase of `text` ("car, road"), merged (the per-pixel maximum); `None` when nothing
+/// matches.
+fn text_logits(model: &mut Sam3, enc: &mut Encoded, text: &str) -> Result<Option<Vec<f32>>, String> {
+    let mut merged: Option<Vec<f32>> = None;
+    for phrase in text.split([',', ';']).map(str::trim).filter(|p| !p.is_empty()) {
+        if let Some(p) = model.segment_text(enc, phrase, 0.5).map_err(|e| e.to_string())? {
+            merged = Some(match merged {
+                None => p.logits,
+                Some(m) => m.iter().zip(&p.logits).map(|(a, b)| a.max(*b)).collect(),
+            });
+        }
+    }
+    Ok(merged)
+}
+
+fn run_job(state: &mut State, shared: &Shared, job: &mut Job) -> Result<Option<SegMask>, String> {
+    let side = lightcraft_segment::MASK_SIDE;
+    match std::mem::replace(&mut job.kind, Kind::Prepare) {
+        Kind::Prepare => {
+            encoded(state, shared, job)?;
+            Ok(None)
+        }
+        Kind::Clicks(clicks) => {
+            let (m, enc) = encoded(state, shared, job)?;
+            let p = m.segment_clicks(enc, &clicks).map_err(|e| e.to_string())?;
+            Ok(Some(SegMask::from_logits(side, &p.logits)))
+        }
+        Kind::Text(text) => {
+            let (m, enc) = encoded(state, shared, job)?;
+            Ok(text_logits(m, enc, &text)?.map(|l| SegMask::from_logits(side, &l)))
+        }
+        #[cfg(test)]
+        #[allow(clippy::panic)]
+        Kind::Panic => panic!("a test panic"),
+        Kind::Detail { prompt, region } => {
+            let input = render(job)?;
+            let m = model(state, shared, &job.dir)?;
+            let t = web_time::Instant::now();
+            let mut enc = m.encode(&input.rgb, input.w, input.h).map_err(|e| e.to_string())?;
+            let (rw, rh) = (region[2] - region[0], region[3] - region[1]);
+            if !(rw > 0.0 && rh > 0.0) {
+                return Ok(None);
+            }
+            let logits = match prompt {
+                Prompt::Clicks(clicks) => {
+                    let inside: Vec<lightcraft_segment::Click> = clicks
+                        .iter()
+                        .map(|c| ((c.at.x - region[0]) / rw, (c.at.y - region[1]) / rh, c.include))
+                        .filter(|(x, y, _)| (0.0..=1.0).contains(x) && (0.0..=1.0).contains(y))
+                        .map(|(x, y, positive)| lightcraft_segment::Click { x: x as f32, y: y as f32, positive })
+                        .collect();
+                    if !inside.iter().any(|c| c.positive) {
+                        return Ok(None);
+                    }
+                    Some(m.segment_clicks(&mut enc, &inside).map_err(|e| e.to_string())?.logits)
+                }
+                Prompt::Text(text) => text_logits(m, &mut enc, &text)?,
+            };
+            log::info!("SAM 3 detail pass ({}×{}) in {:?}", input.w, input.h, t.elapsed());
+            Ok(logits.map(|l| SegMask::from_logits_in(side, &l, region)))
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn job(tag: Tag, reply: &mpsc::Sender<Outcome>) -> Job {
+        // an empty folder: loading fails with an error (no model files)
+        let dir = std::env::temp_dir().join(format!("lc-sam3-worker-none-{}", std::process::id()));
+        Job { dir, key: 1, render: None, missing: None, kind: Kind::Prepare, tag, reply: reply.clone() }
+    }
+
+    #[test]
+    fn errors_come_back_and_the_counters_return_to_zero() {
+        let mut w = Worker::default();
+        let (tx, rx) = mpsc::channel();
+        for _ in 0..3 {
+            w.submit(job(Tag::Wait, &tx)).unwrap();
+        }
+        for _ in 0..3 {
+            let o = rx.recv_timeout(Duration::from_secs(30)).unwrap();
+            assert!(o.result.unwrap_err().contains("not found"));
+        }
+        let t = web_time::Instant::now();
+        while w.pending() > 0 && t.elapsed() < Duration::from_secs(5) {
+            std::thread::yield_now();
+        }
+        assert_eq!(w.pending(), 0);
+        assert!(!w.encoding() && !w.loaded());
+    }
+
+    #[test]
+    fn a_panic_in_a_job_is_an_error_and_the_worker_carries_on() {
+        let shared = Shared::default();
+        let (tx, rx) = mpsc::channel();
+        let (jtx, jrx) = mpsc::channel();
+        let mut j = job(Tag::Wait, &tx);
+        j.kind = Kind::Panic;
+        jtx.send(j).unwrap();
+        jtx.send(job(Tag::Wait, &tx)).unwrap();
+        shared.pending.store(2, Ordering::SeqCst);
+        drop(jtx);
+        run(&jrx, &shared, Duration::from_secs(60));
+        let first = rx.recv().unwrap();
+        assert!(first.result.unwrap_err().contains("failed unexpectedly"));
+        let second = rx.recv().unwrap();
+        assert!(second.result.is_err(), "the next job still runs");
+        assert_eq!(shared.pending.load(Ordering::SeqCst), 0, "counters reset");
+        assert!(!shared.encoding.load(Ordering::SeqCst));
+    }
+
+    #[test]
+    fn a_newer_request_for_the_same_selection_supersedes_a_queued_one() {
+        let (tx, rx) = mpsc::channel();
+        let (jtx, jrx) = mpsc::channel();
+        let clicks = |n: usize| Tag::Clicks {
+            photo: lightcraft_catalog::PhotoId(1),
+            mask: 1,
+            comp: 0,
+            hint: vec![lightcraft_geom::Point::new(0.5, 0.5); n],
+            exclude: vec![],
+        };
+        for n in 1..=3 {
+            jtx.send(job(clicks(n), &tx)).unwrap();
+        }
+        drop(jtx);
+        let shared = Shared::default();
+        shared.pending.store(3, Ordering::SeqCst);
+        run(&jrx, &shared, Duration::from_secs(60));
+        let out: Vec<Outcome> = rx.try_iter().collect();
+        assert_eq!(out.len(), 3);
+        assert!(out[0].superseded && out[1].superseded && !out[2].superseded);
+        assert_eq!(shared.pending.load(Ordering::SeqCst), 0);
+    }
+}
@@ -99,6 +99,7 @@ pub struct SidecarData {
    pub alt_text: Option<String>,
    pub extended_description: Option<String>,
    pub keywords: Option<Vec<String>>,
+    pub regions: Option<Vec<lightcraft_meta::Region>>,
    /// Capture time (ISO 8601) from `exif:DateTimeOriginal`, `photoshop:DateCreated` or
    /// `xmp:CreateDate` (first found). Used only when the file itself has no capture time.
    pub captured: Option<String>,
@@ -133,6 +134,12 @@ pub fn parse_sidecar(xmp: &str, raw: bool) -> std::result::Result<SidecarData, S
        alt_text: m.alt_text.clone(),
        extended_description: m.extended_description.clone(),
        keywords: (!m.keywords.is_empty()).then(|| m.keywords.clone()),
+        // A sidecar that has `mwg-rs:Regions` at all (even an empty list) was written by an app that
+        // knows about regions, so it's authoritative: its list, empty or not, replaces the catalog's.
+        // One without it (most writers, LightCraft's own included, which keeps another app's
+        // `mwg-rs:Regions` byte for byte but never writes one) says nothing about regions, and the
+        // photo's are kept.
+        regions: d.values.contains_key("mwg-rs:Regions").then(|| m.regions.clone()),
        captured: m.capture_time.map(|d| d.to_iso()),
        ..Default::default()
    };
@@ -202,6 +209,9 @@ pub fn merge_into(p: &mut Photo, sc: &SidecarData, now: &str) -> bool {
    if let Some(k) = &sc.keywords {
        m.keywords = k.clone();
    }
+    if let Some(r) = &sc.regions {
+        m.regions = r.clone();
+    }
    let develop = match &sc.develop {
        Some(DevelopPatch::Full(s)) => (**s).clone(),
        Some(DevelopPatch::Partial(v)) => {
				`@@ -0,0 +1 @@`
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truncated