fix: WebSocket connection leaked on WebRTC player cleanup

The connect() function creates a WebSocket but never stores the
reference. The useEffect cleanup only closes the RTCPeerConnection
via pcRef, leaving the WebSocket open.

Each time the component re-renders with changed deps (camera switch,
playback toggle, microphone toggle), a new WebSocket is created
without closing the previous one. This leaks connections until the
browser garbage-collects them or the server times out.

Store the WebSocket in a ref and close it in the cleanup function.

web/src/components/player/WebRTCPlayer.tsx

@@ -52,6 +52,7 @@ export default function WebRtcPlayer({
   // camera states
 
   const pcRef = useRef<RTCPeerConnection | undefined>(undefined);
+  const wsRef = useRef<WebSocket | null>(null);
   const videoRef = useRef<HTMLVideoElement | null>(null);
   const [bufferTimeout, setBufferTimeout] = useState<NodeJS.Timeout>();
   const videoLoadTimeoutRef = useRef<NodeJS.Timeout>(undefined);
@@ -129,7 +130,8 @@ export default function WebRtcPlayer({
       }
 
       pcRef.current = await aPc;
-      const ws = new WebSocket(wsURL);
+      wsRef.current = new WebSocket(wsURL);
+      const ws = wsRef.current;
 
       ws.addEventListener("open", () => {
         pcRef.current?.addEventListener("icecandidate", (ev) => {
@@ -183,6 +185,10 @@ export default function WebRtcPlayer({
     connect(aPc);
 
     return () => {
+      if (wsRef.current) {
+        wsRef.current.close();
+        wsRef.current = null;
+      }
       if (pcRef.current) {
         pcRef.current.close();
         pcRef.current = undefined;