- backend/internal/web/router.go: staticDir string -> staticFS fs.FS; /healthz uses HealthzHandler(); /readyz registered with ReadyzHandler(pinger); embedded FS served via fs.Sub()
- backend/cmd/web/main.go: import assets "backend"; db.RunMigrations(ctx, pool, assets.Migrations) before router; web.NewRouter now receives assets.Static
- All *_test.go NewRouter call sites updated from "./static" to os.DirFS("./static"); "os" import added where missing
- Expand stubbedFileStorer with deletedKey tracking and deleteErr injection field
- Implement TestFileDownload (FILE-04): 302 redirect to presigned URL
- Implement TestFileDownload_NonOwner: non-owner gets 404
- Implement TestFileDelete (FILE-05): HTMX delete, S3+DB both deleted
- Implement TestFileDelete_S3Failure: S3 error does not abort DB delete, 200 returned
- Implement TestFileOwnership (FILE-06): non-owner gets 404 on all three routes
