CI: nightly release dry run (#2052)

release.yml also runs nightly on main with craft-common-actions' dry-run: every release build
except macOS, with nothing signed, pushed or drafted. Breakage that only the release build hits
(riscv64, Flatpak, FreeBSD, packaging) then shows up the next morning instead of on release
day, as it did on 11 Nov 2026.

.github/workflows/release.yml

@@ -1,6 +1,10 @@
 name: Release
 
 on:
+  # A nightly dry run on main: every release build except macOS, nothing signed or released
+  # (craft-common-actions release.yml `dry-run`). Finds release-only breakage before release day.
+  schedule:
+    - cron: "16 1 * * *"
   push:
     branches: [release]
   workflow_dispatch:
@@ -30,6 +34,7 @@ jobs:
     # Intentionally tracked at @main (not SHA-pinned) so org-wide CI improvements, security fixes, and build optimizations propagate without PR churn across all craftapp repos.
     uses: storytold/craft-common-actions/.github/workflows/release.yml@main
     with:
+      dry-run: ${{ github.event_name == 'schedule' }}
       app-name: deckcraft
       app-title: DeckCraft
       # Keep identical to ci.yml and freebsd.yml. The shared release workflow sets