feat: 第一阶段基础框架搭建

后端 (Laravel 10 + Sanctum):
- RBAC 四层权限系统 (users→roles→permissions→menus)
- 门店隔离中间件 (BelongsToStore Trait + StoreIsolation Middleware)
- 操作日志中间件 (自动记录写操作)
- 权限检查中间件 (CheckPermission)
- 16张数据库表迁移 (系统基础+RBAC+字典+配置)
- 11个 Eloquent Model
- Auth API (登录/登出/用户信息)
- 系统设置模块 CRUD (门店/部门/职务/用户/角色/菜单/权限/字典/日志)
- 45条 RESTful API 路由
- InitSeeder 初始数据 (超管/角色/76权限/31菜单)

前端 (Vue 3 + Element Plus + Vite):
- Axios 请求封装 + Token 注入
- Pinia 状态管理 (user + permission store)
- 动态路由 (服务端菜单→前端路由自动生成)
- 后台布局 (侧边栏+顶栏+主内容区)
- 登录页 + 仪表盘首页
- 系统设置 7 个 CRUD 页面

技术方案文档 (7卷):
- 技术总览/数据库设计/API规范/RBAC设计/模块详设/小程序设计/部署方案

backend/app/Models/Permission.php

@@ -0,0 +1,53 @@
+<?php
+
+namespace App\Models;
+
+use App\Enums\PermissionType;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsToMany;
+use Illuminate\Database\Eloquent\Relations\HasMany;
+
+class Permission extends Model
+{
+    protected $fillable = [
+        'parent_id', 'name', 'code', 'module', 'type', 'description', 'sort',
+    ];
+
+    protected $casts = [
+        'type' => PermissionType::class,
+    ];
+
+    public function children(): HasMany
+    {
+        return $this->hasMany(self::class, 'parent_id');
+    }
+
+    public function roles(): BelongsToMany
+    {
+        return $this->belongsToMany(Role::class, 'role_permission');
+    }
+
+    /**
+     * 获取权限树
+     */
+    public static function tree(): array
+    {
+        $all = self::orderBy('sort')->get()->toArray();
+        return self::buildTree($all);
+    }
+
+    private static function buildTree(array $items, int $parentId = 0): array
+    {
+        $tree = [];
+        foreach ($items as $item) {
+            if ($item['parent_id'] == $parentId) {
+                $children = self::buildTree($items, $item['id']);
+                if ($children) {
+                    $item['children'] = $children;
+                }
+                $tree[] = $item;
+            }
+        }
+        return $tree;
+    }
+}