Add in-app + real-time notifications (SignalR/mock, Iran-friendly)

- AppNotification + OnlineService.onNotification (hub event + mock periodic) —
  no FCM/APNs (blocked in Iran); uses the existing realtime channel
- notification-store + pushNotification(); 🔔 bell with unread badge in TopBar,
  notifications screen, global toaster (plays notify sfx)
- Wired events: daily reward, post-match achievements, friend requests
- Closed-app push (Pushe/Najva/Chabok) noted as a later step (needs provider keys)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/lib/i18n.tsx

@@ -226,6 +226,9 @@ const fa: Dict = {
   "reactions.title": "شکلک",
   "stickers.title": "استیکر",
 
+  "notif.title": "اعلان‌ها",
+  "notif.empty": "اعلانی ندارید",
+
   "settings.audio": "تنظیمات صدا",
   "settings.sound": "افکت صدا",
   "settings.music": "موسیقی پس‌زمینه",
@@ -449,6 +452,9 @@ const en: Dict = {
   "reactions.title": "Emoji",
   "stickers.title": "Stickers",
 
+  "notif.title": "Notifications",
+  "notif.empty": "No notifications yet",
+
   "settings.audio": "Audio",
   "settings.sound": "Sound effects",
   "settings.music": "Background music",