feat(config): 新增用户前端访问开关

新增 `frontend_enable` 配置并接入后台站点设置，
用于控制用户首页、订阅入口及用户侧 API 是否对外开放。

开关关闭时相关用户入口统一返回空 404，
同时保留节点 API、管理后台与外部回调接口可访问。

补充特性测试覆盖默认开启、关闭隐藏与节点接口白名单场景

app/Http/Routes/V1/ClientRoute.php

@@ -11,7 +11,7 @@ class ClientRoute
     {
         $router->group([
             'prefix' => 'client',
-            'middleware' => 'client'
+            'middleware' => ['user.frontend', 'client']
         ], function ($router) {
             // Client
             $router->get('/subscribe', [ClientController::class, 'subscribe'])->name('client.subscribe.legacy');

app/Http/Routes/V1/GuestRoute.php

@@ -14,14 +14,18 @@ class GuestRoute
         $router->group([
             'prefix' => 'guest'
         ], function ($router) {
-            // Plan
-            $router->get('/plan/fetch', [PlanController::class, 'fetch']);
+            $router->group([
+                'middleware' => 'user.frontend'
+            ], function ($router) {
+                // Plan
+                $router->get('/plan/fetch', [PlanController::class, 'fetch']);
+                // Comm
+                $router->get('/comm/config', [CommController::class, 'config']);
+            });
             // Telegram
             $router->post('/telegram/webhook', [TelegramController::class, 'webhook']);
             // Payment
             $router->match(['get', 'post'], '/payment/notify/{method}/{uuid}', [PaymentController::class, 'notify']);
-            // Comm
-            $router->get('/comm/config', [CommController::class, 'config']);
         });
     }
 }

app/Http/Routes/V1/PassportRoute.php

@@ -10,7 +10,8 @@ class PassportRoute
     public function map(Registrar $router)
     {
         $router->group([
-            'prefix' => 'passport'
+            'prefix' => 'passport',
+            'middleware' => 'user.frontend'
         ], function ($router) {
             // Auth
             $router->post('/auth/register', [AuthController::class, 'register']);

app/Http/Routes/V1/UserRoute.php

@@ -22,7 +22,7 @@ class UserRoute
     {
         $router->group([
             'prefix' => 'user',
-            'middleware' => 'user'
+            'middleware' => ['user.frontend', 'user']
         ], function ($router) {
             // User
             $router->get('/resetSecurity', [UserController::class, 'resetSecurity']);

app/Http/Routes/V2/ClientRoute.php

@@ -10,7 +10,7 @@ class ClientRoute
     {
         $router->group([
             'prefix' => 'client',
-            'middleware' => 'client'
+            'middleware' => ['user.frontend', 'client']
         ], function ($router) {
             // App
             $router->get('/app/getConfig', [AppController::class, 'getConfig']);

app/Http/Routes/V2/UserRoute.php

@@ -10,7 +10,7 @@ class UserRoute
     {
         $router->group([
             'prefix' => 'user',
-            'middleware' => 'user'
+            'middleware' => ['user.frontend', 'user']
         ], function ($router) {
             // User
             $router->get('/resetSecurity', [UserController::class, 'resetSecurity']);