fix(realtime): flush activity state during forced disconnect cleanup

app/realtime/service.py

@@ -347,6 +347,7 @@ class RealtimeGateway:
             await self._publish_chat_event(chat_id, event=event_name, payload=payload)
 
     async def _cleanup_disconnected_user(self, user_id: int) -> None:
+        await self._flush_user_activity(user_id)
         self._connections.pop(user_id, None)
         affected_chat_ids: list[int] = []
         for chat_id, subscribers in list(self._chat_subscribers.items()):