feat(export): add open-chat window from session list

src/App.tsx

@@ -60,6 +60,7 @@ function App() {
   const isOnboardingWindow = location.pathname === '/onboarding-window'
   const isVideoPlayerWindow = location.pathname === '/video-player-window'
   const isChatHistoryWindow = location.pathname.startsWith('/chat-history/')
+  const isStandaloneChatWindow = location.pathname === '/chat-window'
   const isNotificationWindow = location.pathname === '/notification-window'
   const isExportRoute = location.pathname === '/export'
   const [themeHydrated, setThemeHydrated] = useState(false)
@@ -361,6 +362,12 @@ function App() {
     return <ChatHistoryPage />
   }
 
+  // 独立会话聊天窗口（仅显示聊天内容区域）
+  if (isStandaloneChatWindow) {
+    const sessionId = new URLSearchParams(location.search).get('sessionId') || ''
+    return <ChatPage standaloneSessionWindow initialSessionId={sessionId} />
+  }
+
   // 独立通知窗口
   if (isNotificationWindow) {
     return <NotificationWindow />