支付确认强一致化: 订单推进与标 paid 合并为单事务

confirmPaid 原为「先 ConfirmPaidFromChannel 独立事务推进订单, 再 Updates 标 paid」两步非原子, 崩溃在中间会出现订单已 pending_handoff 但 payment 仍 paying 的不一致窗口, 恢复依赖渠道回调重发而非事务闭环。

改造:
- 新增 ConfirmPaidFromChannelTx(tx, orderID) 让 order 模块共享 payment 模块的外部事务, 订单推进与 payment 标 paid 落进同一事务, 崩溃一致性窗口消除
- NotifyNewConversation 提到事务提交后触发, 避免事务回滚后误发会话通知
- payment_orders 加行锁后 Updates, 防并发回调覆盖写
- 删除未使用的 providerBizNo 死参数

锁顺序全局一致 (order→listing→account→payment), 与 payment_start/refund/Cancel 路径无反向加锁, 无死锁风险。

新增集成测试:
- 正向: 验证 confirmPaid 后 order/listing/account/payment 全部正确推进
- 回滚: payment 更新失败时 order 不残留 pending_handoff, 验证事务原子性

go build/vet/test 通过。

backend/internal/modules/payment/channel_status.go

@@ -4,6 +4,9 @@ import (
 	"context"
 	"hfb_sys/backend/internal/model"
 	"time"
+
+	"gorm.io/gorm"
+	"gorm.io/gorm/clause"
 )
 
 func (r *Repository) applyChannelStatus(ctx context.Context, payment *model.PaymentOrder, status string, payTime string, raw map[string]string, source string) error {
@@ -34,24 +37,41 @@ func (r *Repository) updateChannelStatus(ctx context.Context, paymentID uint64,
 	return r.db.WithContext(ctx).Model(&model.PaymentOrder{}).Where("id = ?", paymentID).Updates(updates).Error
 }
 func (r *Repository) confirmPaid(ctx context.Context, payment *model.PaymentOrder, status string, paidAt time.Time, raw map[string]string, source string) error {
-	if payment.Status != "paid" && payment.OrderID != 0 {
-		if r.orderRepo == nil {
-			return ErrDependencyUnavailable
+	var newConvID uint64
+	err := r.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
+		if payment.OrderID != 0 {
+			if r.orderRepo == nil {
+				return ErrDependencyUnavailable
+			}
+			convID, err := r.orderRepo.ConfirmPaidFromChannelTx(tx, payment.OrderID)
+			if err != nil {
+				return err
+			}
+			newConvID = convID
 		}
-		if err := r.orderRepo.ConfirmPaidFromChannel(ctx, payment.OrderID, firstNonEmpty(payment.ProviderOrderID, payment.PaymentNo)); err != nil {
+
+		var latest model.PaymentOrder
+		if err := tx.Clauses(clause.Locking{Strength: "UPDATE"}).First(&latest, payment.ID).Error; err != nil {
 			return err
 		}
+		updates := map[string]any{
+			"status":            "paid",
+			"provider_order_id": firstNonEmpty(raw["provider_order_id"], raw["leshua_order_id"], raw["pay_order_no"], raw["trade_no"], latest.ProviderOrderID),
+			"raw_response":      jsonMap(withRawSource(raw, source)),
+			"paid_at":           paidAt,
+		}
+		if source == channelSourceNotify {
+			updates["notified_at"] = time.Now()
+		}
+		return tx.Model(&model.PaymentOrder{}).Where("id = ?", payment.ID).Updates(updates).Error
+	})
+	if err != nil {
+		return err
 	}
-	updates := map[string]any{
-		"status":            "paid",
-		"provider_order_id": firstNonEmpty(raw["provider_order_id"], raw["leshua_order_id"], raw["pay_order_no"], raw["trade_no"], payment.ProviderOrderID),
-		"raw_response":      jsonMap(withRawSource(raw, source)),
-		"paid_at":           paidAt,
+	if newConvID > 0 && r.orderRepo != nil {
+		r.orderRepo.NotifyNewConversation(newConvID)
 	}
-	if source == channelSourceNotify {
-		updates["notified_at"] = time.Now()
-	}
-	return r.db.WithContext(ctx).Model(&model.PaymentOrder{}).Where("id = ?", payment.ID).Updates(updates).Error
+	return nil
 }
 func (r *Repository) markPaymentFailed(ctx context.Context, paymentID uint64, raw map[string]string, message string) error {
 	if raw == nil {