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/vitest.setup.ts

@@ -15,17 +15,16 @@ vi.mock('@tanstack/svelte-query', async (orig) => {
   return { ...actual, useQueryClient: () => ({ invalidateQueries: vi.fn() }) };
 });
 
-// Default SvelteKit app-module mocks for the whole suite (#3943). Without
-// them, any page or component that reaches $app/navigation or $app/state —
-// the home page does, through AlbumCard → AlbumMenu — loads SvelteKit's
-// client runtime, whose $app/paths reads __SVELTEKIT_PAYLOAD__ at module
-// load. That global only exists when the kit plugin's define reaches the
-// module, which it does not reliably under vitest: page.test.ts failed to
-// load on one CI run and passed on the re-run of the same commit (#374
-// was the same class). Stubbing the modules keeps every test off the
-// client bootstrap. Tests that assert on goto or need a particular URL
-// still mock per file (pageUrlModule in test-utils/mocks/appState.ts),
-// and per-file mocks win over these.
+// Default SvelteKit app-module mocks for the whole suite. Without them, any
+// page or component that reaches $app/navigation or $app/state — the home page
+// does, through AlbumCard → AlbumMenu — loads SvelteKit's client runtime, whose
+// $app/paths reads __SVELTEKIT_PAYLOAD__ at module load. That global only
+// exists when the kit plugin's define reaches the module, which it does not
+// reliably under vitest, so a page test can fail to load on one run and pass on
+// the next. Stubbing the modules keeps every test off the client bootstrap.
+// Tests that assert on goto or need a particular URL still mock per file
+// (pageUrlModule in test-utils/mocks/appState.ts), and per-file mocks win over
+// these.
 vi.mock('$app/navigation', () => ({
   goto: vi.fn(() => Promise.resolve()),
   invalidate: vi.fn(() => Promise.resolve()),