修正代理主钱包余额快照口径

代理主钱包扣款流水必须记录扣款前后的真实余额，避免资金概况与流水展示出现双重扣减错觉。

Constraint: 项目禁止自动化测试，使用构建和数据库对账验证。

Rejected: 在资金汇总接口按历史充值总量或流水末条余额展示 | 资金概况口径应来自主钱包剩余余额。

Confidence: high

Scope-risk: narrow

Directive: 修改代理钱包扣款链路时必须同时维护余额字段与流水快照一致性。

Tested: go build ./...；migrate up 已执行到 141；只读 SQL 对账确认主钱包余额、成功流水累计、最新流水余额一致且 mismatch_tx_count=0。

Not-tested: 未新增自动化测试（项目规范禁止）。

internal/service/order/service.go

@@ -987,14 +987,17 @@ func (s *Service) getCostPrice(ctx context.Context, shopID uint, packageID uint)
 // createWalletTransaction 创建钱包流水记录
 // ctx: 上下文
 // tx: 事务对象
-// walletID: 钱包ID
+// wallet: 扣款前的钱包快照
 // orderID: 订单ID
 // amount: 扣款金额（正数）
 // purchaseRole: 订单角色
 // relatedShopID: 关联店铺ID（代购场景填充下级店铺ID）
-func (s *Service) createWalletTransaction(ctx context.Context, tx *gorm.DB, walletID uint, orderID uint, amount int64, purchaseRole string, relatedShopID *uint) error {
+func (s *Service) createWalletTransaction(ctx context.Context, tx *gorm.DB, wallet *model.AgentWallet, orderID uint, amount int64, purchaseRole string, relatedShopID *uint) error {
 	var subtype *string
 	remark := "购买套餐"
+	if purchaseRole == "" {
+		purchaseRole = model.PurchaseRoleSelfPurchase
+	}
 
 	// 根据订单角色确定交易子类型和备注
 	switch purchaseRole {
@@ -1021,36 +1024,24 @@ func (s *Service) createWalletTransaction(ctx context.Context, tx *gorm.DB, wall
 
 	// 创建钱包流水记录
 	transaction := &model.AgentWalletTransaction{
-		AgentWalletID:      walletID,
-		ShopID:             0, // 将在下面从钱包记录获取
+		AgentWalletID:      wallet.ID,
+		ShopID:             wallet.ShopID,
 		UserID:             userID,
 		TransactionType:    constants.AgentTransactionTypeDeduct,
 		TransactionSubtype: subtype,
 		Amount:             -amount, // 扣款为负数
-		BalanceBefore:      0,       // 将在下面填充
-		BalanceAfter:       0,       // 将在下面填充
+		BalanceBefore:      wallet.Balance,
+		BalanceAfter:       wallet.Balance - amount,
 		Status:             constants.TransactionStatusSuccess,
 		ReferenceType:      strPtr(constants.ReferenceTypeOrder),
 		ReferenceID:        &orderID,
 		RelatedShopID:      relatedShopID,
 		Remark:             &remark,
 		Creator:            userID,
-		ShopIDTag:          0, // 将在下面填充
-		EnterpriseIDTag:    nil,
+		ShopIDTag:          wallet.ShopIDTag,
+		EnterpriseIDTag:    wallet.EnterpriseIDTag,
 	}
 
-	// 查询钱包记录，获取 shop_id 和余额信息
-	var wallet model.AgentWallet
-	if err := tx.Where("id = ?", walletID).First(&wallet).Error; err != nil {
-		return errors.Wrap(errors.CodeDatabaseError, err, "查询钱包信息失败")
-	}
-
-	transaction.ShopID = wallet.ShopID
-	transaction.ShopIDTag = wallet.ShopIDTag
-	transaction.EnterpriseIDTag = wallet.EnterpriseIDTag
-	transaction.BalanceBefore = wallet.Balance
-	transaction.BalanceAfter = wallet.Balance - amount
-
 	if err := tx.Create(transaction).Error; err != nil {
 		return errors.Wrap(errors.CodeDatabaseError, err, "创建钱包流水失败")
 	}
@@ -1122,7 +1113,7 @@ func (s *Service) createOrderWithWalletPayment(ctx context.Context, order *model
 		if order.PurchaseRole == model.PurchaseRolePurchaseForSubordinate {
 			relatedShopID = &buyerShopID
 		}
-		if err := s.createWalletTransaction(ctx, tx, wallet.ID, order.ID, actualAmount, order.PurchaseRole, relatedShopID); err != nil {
+		if err := s.createWalletTransaction(ctx, tx, wallet, order.ID, actualAmount, order.PurchaseRole, relatedShopID); err != nil {
 			return err
 		}
 
@@ -1602,6 +1593,10 @@ func (s *Service) WalletPay(ctx context.Context, orderID uint, buyerType string,
 				return errors.New(errors.CodeInsufficientBalance, "余额不足或并发冲突")
 			}
 
+			if err := s.createWalletTransaction(ctx, tx, wallet, order.ID, order.TotalAmount, order.PurchaseRole, nil); err != nil {
+				return err
+			}
+
 			if err := s.createWalletPaymentRecord(tx, order, model.PaymentByWallet); err != nil {
 				return err
 			}