fix(frontend): skip hash anchor navigation until session is validated

Avoid chat day fetches with empty session_id on the login page when a stale URL hash is present.

Co-authored-by: Cursor <cursoragent@cursor.com>

web/src/App.tsx

@@ -1704,8 +1704,14 @@ export default function App() {
     loadDayForAnchorRef.current = chatWindow.loadDayForAnchor;
   }, [chatWindow.loadDayForAnchor]);
 
+  const sessionValidatedRef = useRef(sessionValidated);
+  useEffect(() => {
+    sessionValidatedRef.current = sessionValidated;
+  }, [sessionValidated]);
+
   useEffect(() => {
     const handleHashChange = () => {
+      if (sessionValidatedRef.current !== true) return;
       const parsed = parseAnchorHash(window.location.hash);
       if (!parsed) return;
       const currentActive = activeSessionIdRef.current;

web/src/hooks/useChatWindow.ts

@@ -301,6 +301,7 @@ export function useChatWindow({
   // 跨日锚点拉取: 根据 messageId 拉取所属日分片并合并进窗口
   const loadDayForAnchor = useCallback(
     async (messageId: number): Promise<boolean> => {
+      if (!sessionId) return false;
       for (const b of dayStack) {
         if (b.messages.some((m) => m.serverId === messageId)) {
           return true;