fix(room): fix stale room subscribe after async connect

connect() is async/fire-and-forget — if the user switches rooms while
WS is still connecting, the subscribeRoom() call captures the stale
(activeRoomId) closure value and subscribes to the wrong room. Fix by
re-reading activeRoomIdRef.current after the await so we always subscribe
to the room that is active when the connection actually opens.

src/contexts/room-context.tsx

@@ -248,7 +248,11 @@ export function RoomProvider({
       if (client.getStatus() !== 'open') {
         await client.connect();
       }
-      await client.subscribeRoom(activeRoomId);
+      // Re-check: activeRoomId may have changed while we were waiting for connect.
+      // Use activeRoomIdRef to get the *current* room, not the stale closure value.
+      const roomId = activeRoomIdRef.current;
+      if (!roomId) return;
+      await client.subscribeRoom(roomId);
       loadMoreRef.current?.(null);
     };
     setup();