feat: 开放API产品相关

app/openapi/model/ProductPurchaseLinkModel.php

@@ -0,0 +1,19 @@
+<?php
+declare (strict_types = 1);
+
+namespace app\openapi\model;
+
+use app\common\model\ProductPurchaseLinkBaseModel;
+
+/**
+ * 产品购买链接模型
+ * @mixin \think\Model
+ */
+class ProductPurchaseLinkModel extends ProductPurchaseLinkBaseModel
+{
+    // 关联购买平台
+    public function platform()
+    {
+        return $this->belongsTo(ProductPurchasePlatformModel::class, 'platform_id', 'id')->bind(['platform']);
+    }
+}