🐛 fix(payment): 修复退款功能中的数据关联和金额处理问题

- 修复支付记录查询条件，从使用订单号改为通过订单ID关联查询
- 添加订单存在性验证，防止处理不存在的订单退款
- 修复退款金额单位转换问题，将元转换为分后再进行验证和处理
- 确保退款金额在调用支付接口和更新支付记录时使用一致的单位（分）

packages/mini-payment-mt/src/services/payment.mt.service.ts

@@ -448,8 +448,20 @@ export class PaymentMtService extends GenericCrudService<PaymentMtEntity> {
 
       // 根据订单号查找支付记录
       const paymentRepository = this.dataSource.getRepository(PaymentMtEntity);
+
+      // 首先通过订单号查找对应的订单ID
+      const orderRepository = this.dataSource.getRepository(OrderMt);
+      const order = await orderRepository.findOne({
+        where: { orderNo, tenantId }
+      });
+
+      if (!order) {
+        throw new Error(`订单不存在，订单号: ${orderNo}`);
+      }
+
+      // 通过订单ID查找支付记录
       const payment = await paymentRepository.findOne({
-        where: { outTradeNo: orderNo, tenantId }
+        where: { externalOrderId: order.id, tenantId }
       });
 
       if (!payment) {
@@ -461,8 +473,9 @@ export class PaymentMtService extends GenericCrudService<PaymentMtEntity> {
         throw new Error(`订单支付状态不正确，当前状态: ${payment.paymentStatus}`);
       }
 
-      // 验证退款金额
-      if (refundAmount <= 0 || refundAmount > payment.totalAmount) {
+      // 验证退款金额并转换为整数（分）
+      const refundAmountInCents = Math.round(refundAmount * 100);
+      if (refundAmountInCents <= 0 || refundAmountInCents > payment.totalAmount) {
         throw new Error(`退款金额无效，退款金额: ${refundAmount}, 支付金额: ${payment.totalAmount}`);
       }
 
@@ -479,7 +492,7 @@ export class PaymentMtService extends GenericCrudService<PaymentMtEntity> {
         out_trade_no: payment.outTradeNo,
         out_refund_no: outRefundNo,
         amount: {
-          refund: refundAmount,
+          refund: refundAmountInCents,
           total: payment.totalAmount,
           currency: 'CNY'
         },
@@ -491,7 +504,7 @@ export class PaymentMtService extends GenericCrudService<PaymentMtEntity> {
       // 更新支付记录的退款状态
       payment.refundStatus = PaymentStatus.REFUNDED;
       payment.refundTransactionId = outRefundNo; // 使用退款订单号作为临时退款流水号
-      payment.refundAmount = refundAmount;
+      payment.refundAmount = refundAmountInCents;
       payment.refundTime = new Date();
 
       await paymentRepository.save(payment);