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

app/Models/AdminRole.php

@@ -0,0 +1,38 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsToMany;
+
+class AdminRole extends Model
+{
+    protected $table = 'admin_roles';
+
+    protected $fillable = [
+        'slug',
+        'name',
+    ];
+
+    /** @return BelongsToMany<AdminPermission, AdminRole> */
+    public function permissions(): BelongsToMany
+    {
+        return $this->belongsToMany(
+            AdminPermission::class,
+            'admin_role_permissions',
+            'role_id',
+            'permission_id',
+        );
+    }
+
+    /** @return BelongsToMany<AdminUser, AdminRole> */
+    public function users(): BelongsToMany
+    {
+        return $this->belongsToMany(
+            AdminUser::class,
+            'admin_user_roles',
+            'role_id',
+            'admin_user_id',
+        );
+    }
+}