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/auth/store.svelte.ts

@@ -9,7 +9,7 @@ import { user, setUser } from './user.svelte';
 export { user };
 
 // Weekly client-driven cadence for sending the browser's current IANA
-// timezone to PUT /api/me/timezone (#392 Half B). Tracked in
+// timezone to PUT /api/me/timezone. Tracked in
 // localStorage so the cadence survives tab restarts; bumped after each
 // successful PUT. Failures are swallowed — server keeps its previous
 // value (or 'UTC' default).