fix(payment): harden payment and refund chains

src/AKSRT/Payment/GatewayInterface.php

@@ -40,9 +40,10 @@ interface GatewayInterface {
      *
      * @param string $order_number 订单号
      * @param float  $amount       退款金额
-     * @return array{success: bool, refund_id?: string, message?: string}
+     * @param string $request_id  幂等退款请求号
+     * @return array{success: bool, status?: string, refund_id?: string, request_id?: string, message?: string}
      */
-    public function refund(string $order_number, float $amount): array;
+    public function refund(string $order_number, float $amount, string $request_id = ''): array;
 
     /**
      * 获取网关显示名称