fix chat scroll jumps and move about us to home page

web/app/chat/page.js

@@ -30,6 +30,7 @@ function ChatPage() {
   const pollRef = useRef(null);
   const lastMessageIdRef = useRef(null);
   const fileInputRef = useRef(null);
+  const lastScrolledIdRef = useRef(null);
 
   useEffect(() => {
     if (!authLoading && !user) {
@@ -38,6 +39,10 @@ function ChatPage() {
   }, [authLoading, user, router, conversationIdParam]);
 
   useEffect(() => {
+    if (messages.length === 0) return;
+    const lastMsg = messages[messages.length - 1];
+    if (lastMsg.id === lastScrolledIdRef.current) return;
+    lastScrolledIdRef.current = lastMsg.id;
     const area = messagesAreaRef.current;
     if (!area) return;
     const nearBottom = area.scrollHeight - area.scrollTop - area.clientHeight < 150;