feat: 增强管理员权限管理，添加 RBAC 支持，更新 AdminUser 模型以处理角色和权限，更新登录接口返回权限信息，扩展数据库填充器以同步角色权限

lang/en/admin.php

@@ -5,4 +5,5 @@ return [
     'invalid_captcha' => 'Invalid or expired captcha.',
     'invalid_credentials' => 'Invalid account or password.',
     'account_disabled' => 'This account has been disabled.',
+    'permission_denied' => 'You do not have permission to perform this action.',
 ];