Add affected CI and replayable crash repros (#1224)

* AG4: xtask ci --affected

cargo xtask ci --affected [--base REV] [--dry-run] runs fmt, clippy, tests (nextest + doctests when available), layers, assets (only on asset changes) and wasm (only for affected L0-L4/web crates) for the packages a change can affect: changed files map to the owning package and to packages whose sources read them via ../ paths, expanded to reverse dependents. Workspace-wide inputs (root Cargo.toml, Cargo.lock, .cargo/, xtask/, toolchain, clippy.toml) fall back to full CI. Documented in docs/testing.md, AGENTS.md and CLAUDE.md.

(cherry picked from commit f3ca84fc2ee3948582cbc94e4c99ee510e829540)

(cherry picked from commit 8a2cdcadf447eafa57ab14016beae4420f002af0)
(cherry picked from commit d8a4301bc1)

(cherry picked from commit 36402c61ac2f7e29ecd76a6cfc89365cc2572e0a)

* AO1: fast CI profile, looser timing tests

- [profile.ci] (release without LTO, 16 codegen units); `xtask ci` runs clippy
  and tests with --profile ci instead of --release.
- Wall-clock asserts in engine memory_tick, gpu OpenGL decline and script
  socket tests keep their intent with bounds that survive a loaded machine.
- docs/testing.md and CONTRIBUTING.md mention the profile.

(cherry picked from commit b45c8a379351ebdfda0d7076ad4b740baf6f2087)

(cherry picked from commit fa1ea6a107c4c1936cde89b518a05adc73f2b4b0)
(cherry picked from commit e5d5ed80e9)

(cherry picked from commit d2c67660c70764f9c56880a642ad7f0d004a7f92)

* AG6: journal replay repros

Bug reports become replay scripts and crash regression tests become data files:
- engine::replay: a JSON-lines repro format (start line, command steps with
  expect_error, expect queries with JSON pointer + equals, expect_no_error),
  a never-panicking runner that reports per-step ok/error and the first failure,
  and journal export (from the last project open; saves left out; size-capped).
- journal.export {path?} and help.exportRepro {path?} (not journaled).
- Crash capture: when the last-resort guard catches a panic in the outermost
  command, the journal plus that command is saved to Repros/crash-*.jsonl in the
  settings store (newest 20 kept) and the error names the file.
- Commands run by a journaled command (script steps) are no longer journaled twice.
- effectcraft-cli replay SCRIPT.jsonl [--json] [--keep-going]: exits 1 on a failed
  step, unmet expectation or panic.
- crates/host/tests/repros.rs replays every tests/repros/*.jsonl; three samples
  from past crash fixes (zero frame rate, Layer Settings with no selection,
  New Comp from Selection with hostile overlap).
- Docs: docs/agents.md "Repro scripts"; AGENTS.md: crash fix regression test =
  a .jsonl in tests/repros.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

(cherry picked from commit c38509d7dafe507856c48c78db65e00b94b0cebc)

(cherry picked from commit e55b56dbf76716adfcbfe4cc773df19a74edc419)
(cherry picked from commit 96a63855a9)

(cherry picked from commit c59351ab3bd697f0868e41230dd883960d94a540)

* xtask: ci and ci --affected run cargo test and nextest with --no-fail-fast

One run now lists every failing crate instead of stopping at the first.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019qXL3GPNnY9BSFF2XoU2Yu

(cherry picked from commit e46c7debe738eca62b35bf7392ab77637f6a33ae)

* Agents: confinement write-checks journal.export, help.exportRepro and file.exportTimeline

Review on #859 (split into this PR): their output paths were only read-checked (relative ones
not at all). Test: confinement_covers_every_command_that_writes_a_file.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014d65YdNxQmjRkbXRtP2NwH

* #1224: handle bin-only CI targets and BOM repros without weakening timing tests

* #1224: run the full gate when nextest policy changes

---------

Co-authored-by: Elias <hakifx91@gmail.com>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: FredApps <FredApps@users.noreply.github.com>
Co-authored-by: FredApps <153173854+FredApps@users.noreply.github.com>

docs/testing.md

@@ -3,6 +3,7 @@
 ```sh
 cargo test --workspace     # everything
 cargo xtask ci             # fmt, clippy -D warnings, tests, pdf-deps, lock-patches, layers, assets, wasm
+cargo xtask ci --affected  # the same gates, scoped to crates your change can affect
 ```
 
 The After Effects test projects of `crates/aep` are not in the repository; without them the
@@ -32,6 +33,47 @@ Each crate with several integration-test files has one test binary, `tests/it/ma
 modules are the files in `tests/it/`. Run one file with `cargo test -p <crate> --test it <module>::`
 or `cargo nextest run -p <crate> -E 'binary(it) and test(/^<module>::/)'`.
 
+## Affected-only CI
+
+Use `cargo xtask ci --affected` to run the gates for the crates a change can affect. The full
+`cargo xtask ci` remains the required check before a release and when affected mode falls back
+because a workspace-wide input changed.
+
+```sh
+cargo xtask ci --affected                  # base: the merge-base of HEAD with main
+cargo xtask ci --affected --base HEAD~3    # any git revision
+cargo xtask ci --affected --dry-run        # print the plan only
+```
+
+It collects files that differ from the base (committed, staged, unstaged and untracked), preserving
+Unicode and whitespace in their names. Each file maps to the workspace package whose directory
+holds it and every package whose sources point at it with a `../` literal, such as
+`include_bytes!("../../../assets/fonts/Inter-Regular.ttf")` or
+`concat!(env!("CARGO_MANIFEST_DIR"), "/../../docs/preferences.md")`. Deleted and renamed inputs
+still select their readers, including when the input's entire directory no longer exists.
+
+The affected set is those packages plus everything that depends on them (transitively through
+normal and build dependencies) and every package that uses one of them as a dev-dependency.
+Clippy and tests use the same dev profile as full CI. Both modes use the same test runner:
+nextest plus doctests when installed, otherwise cargo test plus doctests. GPU tests run in one
+libtest process, and the translation report reruns with visible output when ui-egui is affected.
+The audio-backend probe runs before building affected crates.
+
+Formatting, PDF dependency policy, lock-patch and layer checks always run. Assets are checked
+when an asset, an `.attribution` sidecar or `ATTRIBUTION.md` changes. The wasm check selects
+affected L0–L4 and web crates. Every step runs even when an earlier step fails; the final result
+names failed steps and includes timings.
+
+Changes to the root `Cargo.toml`, `Cargo.lock`, `.cargo/`, `xtask/`, `rust-toolchain(.toml)`,
+`clippy.toml` or `.config/nextest.toml` can change every crate's build or test policy, so they run
+the full CI instead and say why. Changes no crate reads (most of `docs/`, `README.md`, `.github/`,
+`packaging/`) only get the cheap checks.
+
+Limits: a crate that reads a repo file at run time through a path that is not a `../` literal in its
+sources is not detected, and building a subset of packages can unify features differently from the
+whole workspace. Non-UTF-8 Git paths stop the command rather than silently omitting checks.
+Run the full `cargo xtask ci` before a release.
+
 ## What the tests cover
 
 - **Engine commands** (`crates/engine/src/tests*.rs`): every command family, including undo and