feat(cms): implement complete SysSiteCMS content management system

Initial implementation of the HomeSysPanel CMS built with Laravel 13.0.
Includes complete admin panel, content management, user authentication,
modular architecture for products/services/chatbot, and marketing tools.

Key features:
- User authentication with email verification and password reset
- Role-based access control (Admin/User with granular permissions)
- Content management (pages, news, FAQ, downloads, galleries, banners)
- Contact management system with subjects and responses
- Marketing tools (email campaigns, visitor analytics, social sharing)
- Modular architecture (Products, Services, Chatbot modules)
- AI Chatbot integration with OpenRouter.ai and LlamaCpp support
- Visitor tracking with geolocation
- SEO optimization with meta tags and Open Graph
- Responsive design with Bootstrap 5
- Dark mode support
- Maintenance mode
- Feature request system

app/Http/Middleware/CheckMaintenanceMode.php

@@ -0,0 +1,44 @@
+<?php
+
+namespace App\Http\Middleware;
+
+use Closure;
+use Illuminate\Http\Request;
+use App\Models\Setting;
+use Illuminate\Support\Facades\Auth;
+use App\Models\User;
+
+class CheckMaintenanceMode
+{
+    /**
+     * Handle an incoming request.
+     *
+     * @param  \Illuminate\Http\Request  $request
+     * @param  \Closure  $next
+     * @return mixed
+     */
+    public function handle(Request $request, Closure $next)
+    {
+        // Se o modo de manutenção estiver ativado
+        if (Setting::get('site_maintenance') === 'on') {
+            
+            // Permite acesso às rotas de login, logout e painel administrativo
+            if ($request->is('login') || $request->is('logout') || $request->is('admin*') || $request->is('password*')) {
+                return $next($request);
+            }
+
+            /** @var \App\Models\User $user */
+            $user = Auth::user();
+            
+            // Permite que administradores continuem acessando o site público
+            if ($user && $user->user_type === 'Admin') {
+                return $next($request);
+            }
+
+            // Para todos os outros usuários ou visitantes, exibe a página de manutenção
+            return response()->view('errors.maintenance', [], 503);
+        }
+
+        return $next($request);
+    }
+}