fix: 后台「访问前台」打开独立公开路由 /home，绕过管理员登录重定向

frontend/src/App.tsx

@@ -161,6 +161,8 @@ const App: React.FC = () => {
             <Route path="portal" element={<UserPortal />} />
           </Route>
 
+          {/* 公开前台首页：不受登录态拦截，供后台「访问前台」直接打开 */}
+          <Route path="/home" element={<LandingPage />} />
           <Route path="*" element={<Navigate to="/" />} />
         </Routes>
       </Suspense>

frontend/src/components/layout/AdminLayout.tsx

@@ -329,7 +329,7 @@ const AdminLayout: React.FC = () => {
 
   const handleVisitFrontend = () => {
 
-    const url = window.location.origin + '/';
+    const url = window.location.origin + '/home';
 
     window.open(url, '_blank');