docs: web comments say what the app does, not how it came to be (#6277)

Rewrites the web app's comments to rule 32. Task, milestone, rule and
spec ids are gone; regression stories are restated as the trap they
guard (public auth routes, the menu's stopPropagation, universal loads
under adapter-static, metric deltas with their margin). Flutter and
Tauri mentions now name the Android app or a native shell, operator
quotes and dates are dropped, and one library's counts no longer
appear outside test fixtures. Verified with a TypeScript-scanner token
comparison (template literals and regex literals re-scanned): only
comment text changed.

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

web/src/lib/media/covers.ts

@@ -1,6 +1,6 @@
 // Fallback cover used when the real cover fails to load (e.g. scanner
 // didn't pick up embedded art and there's no sidecar). Served as a static
-// asset from web/static/placeholders/ so the operator can swap the artwork
+// asset from web/static/placeholders/ so an admin can swap the artwork
 // without touching code. SvelteKit + adapter-static publishes everything
 // under web/static/ at the URL root, and the Go binary embeds the build
 // output, so this resolves identically in dev and production.