fix chat session leak

web/context/ChatWidgetContext.js

@@ -2,11 +2,13 @@
 
 import { createContext, useContext, useState, useRef, useCallback, useEffect } from "react";
 import { createStompClient } from "@/lib/chatSocket";
+import { useAuth } from "@/context/AuthContext";
 
 const ChatWidgetContext = createContext(null);
 const API_BASE = "";
 
 export function ChatWidgetProvider({ children }) {
+  const { user } = useAuth();
   const [isOpen, setIsOpen] = useState(false);
   const [view, setView] = useState("ai"); // "ai" | "history" | "live"
 
@@ -72,6 +74,24 @@ export function ChatWidgetProvider({ children }) {
     }
   }, []);
 
+  const prevUserIdRef = useRef(user?.id);
+  useEffect(() => {
+    const currentId = user?.id ?? null;
+    const prevId = prevUserIdRef.current;
+    prevUserIdRef.current = currentId;
+    if (prevId !== null && prevId !== currentId) {
+      setAiMessages([]);
+      localStorage.removeItem("fc_aiMessages");
+      setConversations([]);
+      setActiveConvId(null);
+      setActiveConv(null);
+      setLiveMessages([]);
+      disconnectStomp();
+      setView("ai");
+      setIsOpen(false);
+    }
+  }, [user?.id, disconnectStomp]);
+
   const subscribeToConversation = useCallback((client, convId) => {
     client.subscribe(`/topic/chat/conversations/${convId}`, (frame) => {
       try {