feat(matchmaking): add automatic requeue on match rejection

- Detect Nakama error code 3 ("No match ID or token found") when a
  match is rejected due to incompatible match properties (e.g., mode mismatch).
- Preserve last selected game mode using a ref so client can requeue
  automatically without user interaction.
- Implement fallback logic to call joinMatchmaker() again after server
  rejection.
- Improve robustness of matchmaking flow by ensuring players remain
  in queue until a valid match is formed.

src/tictactoe/providers/NakamaProvider.tsx

@@ -47,6 +47,8 @@ export function NakamaProvider({ children }: { children: React.ReactNode }) {
   const [session, setSession] = useState<Session | null>(null);
   const [socket, setSocket] = useState<Socket | null>(null);
   const [matchId, setMatchId] = useState<string | null>(null);
+  const lastModeRef = React.useRef<string | null>(null);
+  const socketRef = React.useRef<Socket | null>(null);
 
   // ----------------------------------------------------
   // LOGIN
@@ -62,17 +64,32 @@ export function NakamaProvider({ children }: { children: React.ReactNode }) {
     const s = client.createSocket(undefined, undefined); // no SSL on localhost
     await s.connect(newSession, true);
     setSocket(s);
+    socketRef.current = s;
 
     console.log("[Nakama] WebSocket connected");
 
     // MATCHMAKER MATCHED CALLBACK
     s.onmatchmakermatched = async (matched: MatchmakerMatched) => {
+      // 1) If match_id is empty → server rejected the group.
+      if (!matched.match_id) {
+        console.warn("[Nakama] Match rejected by server. Auto-requeueing...");
+
+        if (lastModeRef.current) {
+          try {
+            await joinMatchmaker(lastModeRef.current);
+          } catch (e) {
+            console.error("[Nakama] Requeue failed:", e);
+          }
+        }
+
+        return;
+      }
+
+      // 2) Valid match: continue as usual.
       console.log("[Nakama] MATCHED:", matched);
-
-      setMatchId(matched.match_id);
-
       try {
         await s.joinMatch(matched.match_id);
+        setMatchId(matched.match_id);
         console.log("[Nakama] Auto-joined match:", matched.match_id);
       } catch (err) {
         console.error("[Nakama] Failed to join match:", err);
@@ -84,6 +101,7 @@ export function NakamaProvider({ children }: { children: React.ReactNode }) {
   // MATCHMAKING
   // ----------------------------------------------------
   async function joinMatchmaker(mode: string) {
+    const socket = socketRef.current;
     if (!socket) throw new Error("socket missing");
 
     console.log(`[Nakama] Matchmaking... with +mode:"${mode}"`);
@@ -94,6 +112,8 @@ export function NakamaProvider({ children }: { children: React.ReactNode }) {
       { mode } // stringProperties
     );
 
+    lastModeRef.current = mode;
+
     return ticket.ticket;
   }