feat(pay): 添加产品类型枚举和兑换率接口

- 新增 ProductType 枚举类，用于定义产品类型
- 添加 ExchangeRepoInterface 接口，用于获取兑换率
- 实现 QueryPointRateTest 测试用例，验证兑换率查询功能

src/Domain/Product/Enum/ProductType.php

@@ -0,0 +1,41 @@
+<?php
+/**
+ * ProductType.php@LuxPay
+ *
+ * @author 李东云 <Dongyun.Li@LuxCreo.Ai>
+ * Powered by PhpStorm
+ * Created on 2025/8/5
+ */
+
+namespace Singularity\HDK\Pay\Domain\Product\Enum;
+
+enum ProductType {
+    case plan;
+
+    case pack;
+
+    case oneTime;
+
+    case renew;
+
+    public static function tryFrom(string $type): ?ProductType
+    {
+        return match ($type) {
+            'plan' => self::plan,
+            'pack' => self::pack,
+            'oneTime' => self::oneTime,
+            'renew' => self::renew,
+            default => null,
+        };
+    }
+
+    public static function names(): array
+    {
+        $result = [];
+        foreach (self::cases() as $case) {
+            $result[] = $case->name;
+        }
+        return $result;
+    }
+
+}

src/Domain/Product/Repository/ExchangeRepoInterface.php

@@ -0,0 +1,22 @@
+<?php
+/**
+ * ExchangeRepoInterface.php@LuxDesign
+ *
+ * @author 李东云 <Dongyun.Li@LuxCreo.Ai>
+ * Powered by PhpStorm
+ * Created on 2025/7/29
+ */
+
+namespace Singularity\HDK\Pay\Domain\Product\Repository;
+
+use Singularity\HDK\Pay\Domain\Account\Enum\PointType;
+
+interface ExchangeRepoInterface
+{
+    /**
+     * @param PointType $source
+     * @param PointType $target
+     * @return float
+     */
+    public function getRate(PointType $source, PointType $target): float;
+}

tests/Feature/Product/QueryPointRateTest.php

@@ -0,0 +1,24 @@
+<?php
+
+/**
+ * QueryPointRateTest.php@Pay
+ *
+ * @author 李东云 <Dongyun.Li@LuxCreo.Ai>
+ * Powered by PhpStorm
+ * Created on 2025/8/18
+ */
+
+use Singularity\HDK\Pay\Domain\Account\Enum\PointType;
+use Singularity\HDK\Pay\Infrastructure\Repository\ProductRepo;
+
+use function Hyperf\Support\make;
+
+it('can query point rate', function () {
+    $repo = make(ProductRepo::class);
+
+    $from = PointType::FtaiAligner;
+    $to = PointType::LuxPoint;
+
+    $rate = $repo->getRate($from, $to);
+    expect($rate)->toBeFloat();
+})->only();