feat: 添加管理员权限管理功能，更新 AdminUser 模型以支持权限加载，扩展 API 路由以管理后台用户及其权限

app/Models/AdminUser.php

@@ -49,10 +49,21 @@ class AdminUser extends Authenticatable
         );
     }
 
+    /** @return BelongsToMany<AdminPermission, AdminUser> */
+    public function permissions(): BelongsToMany
+    {
+        return $this->belongsToMany(
+            AdminPermission::class,
+            'admin_user_permissions',
+            'admin_user_id',
+            'permission_id',
+        );
+    }
+
     /** 是否具备指定权限（含 `super_admin` 角色全放行）。 */
     public function hasAdminPermission(string $slug): bool
     {
-        $this->loadMissing(['roles.permissions']);
+        $this->loadMissing(['roles.permissions', 'permissions']);
 
         foreach ($this->roles as $role) {
             if ($role->slug === self::ROLE_SUPER_ADMIN) {
@@ -65,6 +76,12 @@ class AdminUser extends Authenticatable
             }
         }
 
+        foreach ($this->permissions as $permission) {
+            if ($permission->slug === $slug) {
+                return true;
+            }
+        }
+
         return false;
     }
 
@@ -73,7 +90,7 @@ class AdminUser extends Authenticatable
      */
     public function adminPermissionSlugs(): array
     {
-        $this->loadMissing(['roles.permissions']);
+        $this->loadMissing(['roles.permissions', 'permissions']);
         if ($this->roles->contains('slug', self::ROLE_SUPER_ADMIN)) {
             return AdminPermission::query()->orderBy('slug')->pluck('slug')->all();
         }
@@ -84,7 +101,24 @@ class AdminUser extends Authenticatable
                 $out[$permission->slug] = true;
             }
         }
+        foreach ($this->permissions as $permission) {
+            $out[$permission->slug] = true;
+        }
 
         return array_keys($out);
     }
+
+    /**
+     * @return list<string>
+     */
+    public function adminRoleSlugs(): array
+    {
+        $this->loadMissing('roles');
+
+        return $this->roles
+            ->pluck('slug')
+            ->filter(static fn ($slug): bool => is_string($slug) && $slug !== '')
+            ->values()
+            ->all();
+    }
 }