feat: 初始化进销存数据开放平台项目

初始化完整的前后端项目结构，包含ThinkPHP后端API服务和Next.js前端管理系统，添加基础配置、中间件、模型、路由等核心代码，以及项目文档和静态资源。

thinkphp/app/model/Client.php

@@ -0,0 +1,54 @@
+<?php
+
+namespace app\model;
+
+use think\Model;
+
+class Client extends Model
+{
+    protected $name = 'clients';
+    protected $pk = 'id';
+    protected $autoWriteTimestamp = true;
+    protected $createTime = 'created_at';
+    protected $updateTime = 'updated_at';
+    protected $append = ['api_keys'];
+
+    // 客户类型枚举
+    const TYPE_SUPPLIER = 'supplier';
+    const TYPE_DISTRIBUTOR = 'distributor';
+    const TYPE_HOSPITAL = 'hospital';
+    const TYPE_OTHER = 'other';
+
+    // 状态枚举
+    const STATUS_ENABLED = 1;
+    const STATUS_DISABLED = 0;
+
+    /**
+     * 关联API密钥
+     */
+    public function apiKeys()
+    {
+        return $this->hasMany(ApiKey::class, 'client_id');
+    }
+
+    /**
+     * 获取api_keys字段（下划线命名）
+     */
+    public function getApiKeysAttr()
+    {
+        return $this->apiKeys()->select()->toArray();
+    }
+
+    /**
+     * 获取客户类型列表
+     */
+    public static function getClientTypes()
+    {
+        return [
+            self::TYPE_SUPPLIER => '供应商',
+            self::TYPE_DISTRIBUTOR => '分销商',
+            self::TYPE_HOSPITAL => '医院',
+            self::TYPE_OTHER => '其他',
+        ];
+    }
+}