feat: improve media viewer and push delivery stability

- add unified Android media viewer with swipe navigation, pinch-to-zoom and swipe-to-dismiss\n- move circle videos out of media gallery and surface them in voice/chat info flows\n- align web chat info handling for circle videos and media viewer exclusions\n- stabilize realtime and tablet chat shell updates already staged in this batch\n- fix Celery push delivery loop handling so FCM jobs can read tokens reliably in worker processes

app/notifications/tasks.py

@@ -15,6 +15,19 @@ logger = logging.getLogger(__name__)
 
 
 _firebase_app: firebase_admin.App | None = None
+_worker_loop: asyncio.AbstractEventLoop | None = None
+
+
+def _get_worker_loop() -> asyncio.AbstractEventLoop:
+    global _worker_loop
+    if _worker_loop is None or _worker_loop.is_closed():
+        _worker_loop = asyncio.new_event_loop()
+    return _worker_loop
+
+
+def _run_async(coro):
+    loop = _get_worker_loop()
+    return loop.run_until_complete(coro)
 
 
 def _get_firebase_app() -> firebase_admin.App | None:
@@ -63,7 +76,7 @@ def _send_fcm_to_user(user_id: int, title: str, body: str, data: dict[str, Any])
         logger.info("Skipping FCM send for user=%s: Firebase disabled", user_id)
         return
 
-    tokens = asyncio.run(_load_tokens(user_id))
+    tokens = _run_async(_load_tokens(user_id))
     if not tokens:
         return
 
@@ -83,9 +96,9 @@ def _send_fcm_to_user(user_id: int, title: str, body: str, data: dict[str, Any])
         try:
             messaging.send(message, app=app)
         except messaging.UnregisteredError:
-            asyncio.run(_delete_invalid_token(user_id=user_id, platform=platform, token=token))
+            _run_async(_delete_invalid_token(user_id=user_id, platform=platform, token=token))
         except messaging.SenderIdMismatchError:
-            asyncio.run(_delete_invalid_token(user_id=user_id, platform=platform, token=token))
+            _run_async(_delete_invalid_token(user_id=user_id, platform=platform, token=token))
         except Exception:
             logger.exception("FCM send failed for user=%s platform=%s", user_id, platform)