feat: 高考志愿与定价分销链路更新（管理端/API/小程序）

- 新增高考志愿核心服务、模型、控制器与迁移脚本

- 同步管理端定价/分销/设置与小程序入口、历史、测试选择和支付逻辑

- 补充相关开发文档

Made-with: Cursor

api/app/model/GaokaoOrder.php

@@ -0,0 +1,38 @@
+<?php
+namespace app\model;
+
+use think\Model;
+
+/**
+ * 高考业务订单表
+ */
+class GaokaoOrder extends Model
+{
+    protected $name = 'gaokao_order';
+
+    protected $schema = [
+        'id'             => 'int',
+        'orderNo'        => 'string',
+        'userId'         => 'int',
+        'tenantId'       => 'int',
+        'productCode'    => 'string',
+        'pricingId'      => 'int',
+        'amountOriginal' => 'int',
+        'amountPayable'  => 'int',
+        'amountPaid'     => 'int',
+        'currency'       => 'string',
+        'payStatus'      => 'int',
+        'payChannel'     => 'string',
+        'paidAt'         => 'int',
+        'refundAt'       => 'int',
+        'extJson'        => 'string',
+        'createdAt'      => 'int',
+        'updatedAt'      => 'int',
+    ];
+
+    protected $autoWriteTimestamp = 'int';
+    protected $createTime = 'createdAt';
+    protected $updateTime = 'updatedAt';
+    protected $json = ['extJson'];
+}
+