feat(frontend): implement center auth session flow with route guard

src/layouts/AppLayout.tsx

@@ -1,6 +1,9 @@
 import { Link, Outlet } from 'react-router-dom'
+import { useAuth } from '../auth/auth-context'
 
 export default function AppLayout() {
+  const { isAuthed, session, logout } = useAuth()
+
   return (
     <div style={{ display: 'grid', gridTemplateColumns: '220px 1fr', minHeight: '100vh' }}>
       <aside style={{ borderRight: '1px solid #ddd', padding: 16 }}>
@@ -10,6 +13,18 @@ export default function AppLayout() {
           <Link to="/chat">聊天</Link>
           <Link to="/login">登录</Link>
         </nav>
+        <div style={{ marginTop: 16, fontSize: 12 }}>
+          {isAuthed ? (
+            <>
+              <div>{session?.user.email}</div>
+              <button onClick={() => logout()} style={{ marginTop: 6 }}>
+                登出
+              </button>
+            </>
+          ) : (
+            <span>未登录</span>
+          )}
+        </div>
       </aside>
       <main style={{ padding: 16 }}>
         <Outlet />