refactor(ProductRepo): 优化 getRate 方法参数处理

- 将 getRate 方法的 $uid 参数变更为可选参数
- 使用 array_filter 过滤空值，避免在请求中发送不必要的参数
- 增加了两个单元测试用例，分别测试不带 uid 和带 uid 的情况

src/Infrastructure/Repository/ProductRepo.php

@@ -206,11 +206,11 @@ final class ProductRepo extends AbstractRepo implements RechargeProductRepoInter
      * @return float
      * @throws GuzzleException
      */
-    public function getRate(PointType $source, PointType $target, string $uid): float
+    public function getRate(PointType $source, PointType $target, ?string $uid = null): float
     {
         $response = $this->requestService->requestGet(
             url: "/rpc/v2/products/$target->value/exchange-rate/$source->value",
-            params: ['uid' => $uid]
+            params: array_filter(['uid' => $uid]),
         );
 
         $content = $response->getBody()->getContents();

tests/Feature/Product/QueryPointRateTest.php

@@ -23,4 +23,16 @@ it('can query point rate', function () {
 
     $rate = $repo->getRate($from, $to, $uid);
     expect($rate)->toBeFloat();
-});
+})->only();
+
+it('can query point rate with uid', function () {
+    $repo = make(ProductRepo::class);
+
+    $from = PointType::FtaiAligner;
+    $to = PointType::LuxPoint;
+
+    $uid = 'cn3321';
+
+    $rate = $repo->getRate($from, $to, $uid);
+    expect($rate)->toBeFloat();
+})->only();