Fix read receipts: join chat group when activeChat changes

client-web/src/modules/chats/presentation/ChatPage.tsx

@@ -65,6 +65,8 @@ export default function ChatPage() {
   const [activeTab, setActiveTab] = useState('chats');
   const { t } = useLang();
 
+  const activeChat = useChatStore((state) => state.activeChat);
+
   useEffect(() => {
     groupCallOpenRef.current = groupCallOpen;
     groupCallChatIdRef.current = groupCallChatId;
@@ -335,6 +337,16 @@ export default function ChatPage() {
     };
   }, [user?.id]);
 
+  // Join chat group when activeChat changes
+  useEffect(() => {
+    if (activeChat) {
+      const socket = getSocket();
+      if (socket) {
+        socket.emit('join_chat', activeChat);
+      }
+    }
+  }, [activeChat]);
+
   const handleStartCall = (targetUser: UserBasic, type: 'voice' | 'video') => {
     setCallTarget(targetUser);
     setCallType(type);
@@ -371,8 +383,6 @@ export default function ChatPage() {
     setGroupCallOpen(false);
   };
 
-  const activeChat = useChatStore((state) => state.activeChat);
-
   return (
     <motion.div
       initial={{ opacity: 0 }}