F8.2: open project files through the installed PWA

[Flow-Fly]

Summary

• import .pf, legacy .json, .ase, and .aseprite files as new durable library projects without replacing the active drawing
• register installed-PWA file handlers so desktop Chromium can open Pixel Forge and Aseprite files in the existing app window
• route File-menu selection, operating-system launches, and drag-and-drop through one serialized import path with polite, dismissible feedback
• preserve Aseprite frame links and indexed pixels across immediate persistence/reopen
• validate malformed project data before persistence and roll back imports that fail during hydration
• keep capped imports non-destructive and make tab-limit feedback dismissible and temporary
• isolate palette events per project and serialize the visible pixels instead of stale indexed data

Linked work

Implements #123.

• F8.2a: Import project files as durable library projects #330
• F8.2b: Make Aseprite import context-aware #331
• F8.2c: Register PWA file handlers and consume OS launches #332
• F8.2d: Add drag-and-drop parity and repeatable PWA file tests #333
• Project integrity — eliminate cross-tab and stale-save corruption #337 (confirmed integrity follow-up; the bounded save/tab repairs are included here)

Each child issue has its own implementation commit; the final commits contain the independent-review and integrity repairs.

Verification

• npm run test:run — 96 files, 533 tests passed
• npm run lint -- --quiet
• npm run build
• generated-manifest integration test for file_handlers and launch_handler
• npm run fallow:audit — no new findings
• local browser smoke: workspace restored, editor rendered normally, no new console errors

Manual installed-PWA gate

Run:

npm run pwa:preview

Then uninstall and reinstall Pixel Forge so Chromium refreshes file associations.

• Finder Open With → Pixel Forge opens .pf, .ase, and .aseprite
• opening another file focuses the existing app window and creates a new internal tab
• multiple files retain their launch order
• an import beyond the eight-tab limit remains in Project Library with clear feedback
• drag-and-drop behaves like File-menu import
• denying the browser-owned permission leaves current work unchanged
• Firefox/Safari still start quietly; File-menu import and drag-and-drop remain available

The full repeatable procedure is in docs/verification/pwa.md.

Boundaries

• .json remains a manual/drop import format and is not registered with the operating system
• file handles are not retained
• no write permission is requested
• imported projects never write back to their source files

[Flow-Fly]

I reproduced the important distinction behind the report:

• the destructive replacement matches the pre-F8.2: open project files through the installed PWA #334 importer, which loaded a selected file directly into the active context while keeping its old storage identity
• the current F8.2: open project files through the installed PWA #334 importer rejects a ninth open before save, hydration, activation, or workspace persistence; a real WorkspaceStore integration test now locks that down
• an installed PWA can still run the old importer until the waiting update is restarted or the app is reinstalled

The follow-up commits also fixed deterministic sources of the “previous drawing” artifacts:

• old cels surviving a sequential project load
• temporary/import contexts broadcasting palette remaps into every open tab
• shared hard-linked buffers being remapped repeatedly
• canvas-only edits being saved beside stale indexed pixels

Verification is green: 96 test files / 533 tests, lint, build, and local editor smoke.

Please accept Update ready → Restart (or reinstall the PWA) before retesting the eight-tab case. The expected result is: the active tab is unchanged, the imported project is retained in Project Library, and the feedback disappears after six seconds or via Dismiss.

The remaining broader save-integrity hazards are tracked in #337 rather than silently expanding this PR further.