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/components/NotificationEmailCard.svelte

@@ -10,7 +10,7 @@
   import SettingsGroup from '#lib/components/settings/SettingsGroup.svelte';
   import SettingRow from '#lib/components/settings/SettingRow.svelte';
 
-  // When notification emails go out (M489 #5346). Nothing is emailed per
+  // When notification emails go out. Nothing is emailed per
   // event: new music is a daily summary, everything else a batch.
 
   const button =
@@ -55,8 +55,8 @@
       form = { ...saved };
       pushToast('Notification email schedule saved.');
     } catch (e) {
-      // The server names the field it refused (#3937: errMessage, not
-      // e.message, because the client throws a plain object).
+      // The server names the field it refused (errMessage, not e.message:
+      // the client throws a plain object).
       pushToast(errMessage(e), 'error');
     } finally {
       saving = false;