feat(v2): outbox 退款感知(refund_id 进唯一键)+ 投递门禁放行退款态 + Enqueue 贯通 refundID

internal/gateway/gateway.go

@@ -33,8 +33,9 @@ type ProductResolver interface {
 }
 
 // WebhookEnqueuer receives a domain payload to deliver to the business system.
+// refundID 为退款事件的幂等维度(payment 事件传 "")。
 type WebhookEnqueuer interface {
-	Enqueue(outTradeNo, bizSystem, eventType string, data map[string]any) error
+	Enqueue(outTradeNo, bizSystem, eventType, refundID string, data map[string]any) error
 }
 
 type Gateway struct {

internal/gateway/gateway_test.go

@@ -38,7 +38,7 @@ type spyEnqueuer struct {
 	failNext bool // 置 true 模拟 outbox 入队失败(settle 崩溃窗口测试用)
 }
 
-func (s *spyEnqueuer) Enqueue(outTradeNo, bizSystem, eventType string, data map[string]any) error {
+func (s *spyEnqueuer) Enqueue(outTradeNo, bizSystem, eventType, refundID string, data map[string]any) error {
 	if s.failNext {
 		s.failNext = false
 		return errors.New("outbox down")

internal/gateway/settle.go

@@ -92,7 +92,7 @@ func (g *Gateway) enqueuePaymentSucceeded(att *model.Attempt, paidAt time.Time)
 		"channel":          att.Channel,
 		"paid_at":          paidAt.Format(time.RFC3339),
 	}
-	return g.webhook.Enqueue(o.OutTradeNo, o.BizSystem, "payment.succeeded", data)
+	return g.webhook.Enqueue(o.OutTradeNo, o.BizSystem, "payment.succeeded", "", data)
 }
 
 // HandleCallback runs a channel's raw callback through its Provider.VerifyCallback