update

frontend/src/contexts/ChatContext.tsx

@@ -56,19 +56,43 @@ export const ChatProvider: React.FC<ChatProviderProps> = ({ children }) => {
   const connected = data?.connected ?? false;
   const loginName = data?.loginName ?? null;
 
+  const prevUnreadRef = useRef<Map<string, number>>(new Map());
+  const isInitializedRef = useRef(false);
+
+  // Reset initialization flag when disconnected
+  useEffect(() => {
+    if (!isConnected) {
+      isInitializedRef.current = false;
+    }
+  }, [isConnected]);
+
   // Detect new unread messages while panel is closed and show toast
   useEffect(() => {
     if (!rooms.length) return;
     const prev = prevUnreadRef.current;
-    const isFirstLoad = prev.size === 0;
+
+    if (!isInitializedRef.current) {
+      // First load (or after reconnect) — initialize without toasting
+      for (const room of rooms) {
+        prev.set(room.token, room.unreadMessages);
+      }
+      isInitializedRef.current = true;
+      return;
+    }
 
     for (const room of rooms) {
       const prevCount = prev.get(room.token) ?? 0;
-      if (!isFirstLoad && !chatPanelOpen && room.unreadMessages > prevCount) {
+      if (!chatPanelOpen && room.unreadMessages > prevCount) {
         showNotificationToast(room.displayName, 'info');
       }
       prev.set(room.token, room.unreadMessages);
     }
+
+    // Prune entries for rooms no longer in the list
+    const currentTokens = new Set(rooms.map((r) => r.token));
+    for (const key of prev.keys()) {
+      if (!currentTokens.has(key)) prev.delete(key);
+    }
   }, [rooms, chatPanelOpen, showNotificationToast]);
 
   const selectRoom = useCallback((token: string | null) => {