修复(#139): 申请提现改为事务内 FOR UPDATE 直读 DB

- commissionWithdrawLogic: 不再用 ctx 中可能陈旧的 cache user 做余额校验
- 在事务内 FOR UPDATE user 行 + 求和 pending → 用 DB 真值校验 commission
- 与 approveWithdrawal 对齐数据源，消除 cache/DB 不一致导致的漏报
- 新增 4 个 sqlmock 单测：陈旧 cache 拒绝、happy path、pending 吃光、user 丢失

Co-authored-by: multica-agent <github@multica.ai>

internal/logic/public/user/commissionWithdrawLogic.go

@@ -11,6 +11,7 @@ import (
 	"github.com/perfect-panel/server/pkg/xerr"
 	"github.com/pkg/errors"
 	"gorm.io/gorm"
+	"gorm.io/gorm/clause"
 )
 
 type CommissionWithdrawLogic struct {
@@ -29,7 +30,7 @@ func NewCommissionWithdrawLogic(ctx context.Context, svcCtx *svc.ServiceContext)
 }
 
 func (l *CommissionWithdrawLogic) CommissionWithdraw(req *types.CommissionWithdrawRequest) (resp *types.WithdrawalLog, err error) {
-	u, ok := l.ctx.Value(constant.CtxKeyUser).(*user.User)
+	ctxUser, ok := l.ctx.Value(constant.CtxKeyUser).(*user.User)
 	if !ok {
 		logger.Error("current user is not found in context")
 		return nil, errors.Wrapf(xerr.NewErrCode(xerr.InvalidAccess), "Invalid Access")
@@ -51,28 +52,38 @@ func (l *CommissionWithdrawLogic) CommissionWithdraw(req *types.CommissionWithdr
 		}
 	}
 
-	// Sum all pending (status=0) withdrawals to compute available balance.
-	// Available = commission - pendingTotal; commission is only deducted on approval.
-	var pendingTotal int64
-	if err = l.svcCtx.DB.WithContext(l.ctx).
-		Model(&user.Withdrawal{}).
-		Where("user_id = ? AND status = ?", u.Id, user.WithdrawalStatusPending).
-		Select("COALESCE(SUM(amount), 0)").
-		Scan(&pendingTotal).Error; err != nil {
-		l.Errorf("Failed to query pending withdrawals for user %d: %v", u.Id, err)
-		return nil, errors.Wrapf(xerr.NewErrCode(xerr.DatabaseQueryError), "Failed to query pending withdrawals for user %d", u.Id)
-	}
-
-	if u.Commission < req.Amount+pendingTotal {
-		logger.Errorf("User %d insufficient available commission: total=%d pending=%d requested=%d",
-			u.Id, u.Commission, pendingTotal, req.Amount)
-		return nil, errors.Wrapf(xerr.NewErrCode(xerr.UserCommissionNotEnough), "User %d has insufficient commission balance", u.Id)
-	}
-
+	// HIF-139: read commission and pending total directly from DB inside a
+	// transaction, FOR UPDATE on the user row. The ctxUser snapshot may be
+	// served from cache and can be stale (the original bug allowed a user
+	// with cached commission=996900 to submit a withdrawal while DB said 0,
+	// which then failed admin approval with 20010). Approve already locks
+	// the user row this way; aligning submission closes the gap.
 	var w user.Withdrawal
 	err = l.svcCtx.DB.WithContext(l.ctx).Transaction(func(tx *gorm.DB) error {
+		var dbUser user.User
+		if txErr := tx.Clauses(clause.Locking{Strength: "UPDATE"}).
+			Where("id = ?", ctxUser.Id).First(&dbUser).Error; txErr != nil {
+			l.Errorf("Failed to lock user %d for withdrawal: %v", ctxUser.Id, txErr)
+			return errors.Wrapf(xerr.NewErrCode(xerr.DatabaseQueryError), "Failed to lock user %d: %v", ctxUser.Id, txErr)
+		}
+
+		var pendingTotal int64
+		if txErr := tx.Model(&user.Withdrawal{}).
+			Where("user_id = ? AND status = ?", ctxUser.Id, user.WithdrawalStatusPending).
+			Select("COALESCE(SUM(amount), 0)").
+			Scan(&pendingTotal).Error; txErr != nil {
+			l.Errorf("Failed to query pending withdrawals for user %d: %v", ctxUser.Id, txErr)
+			return errors.Wrapf(xerr.NewErrCode(xerr.DatabaseQueryError), "Failed to query pending withdrawals for user %d", ctxUser.Id)
+		}
+
+		if dbUser.Commission < req.Amount+pendingTotal {
+			logger.Errorf("User %d insufficient available commission: db_commission=%d pending=%d requested=%d",
+				ctxUser.Id, dbUser.Commission, pendingTotal, req.Amount)
+			return errors.Wrapf(xerr.NewErrCode(xerr.UserCommissionNotEnough), "User %d has insufficient commission balance", ctxUser.Id)
+		}
+
 		w = user.Withdrawal{
-			UserId:    u.Id,
+			UserId:    ctxUser.Id,
 			Amount:    req.Amount,
 			Content:   req.Content,
 			Status:    user.WithdrawalStatusPending,
@@ -81,16 +92,19 @@ func (l *CommissionWithdrawLogic) CommissionWithdraw(req *types.CommissionWithdr
 			Account:   req.Account,
 			QrCodeUrl: req.QrCodeUrl,
 		}
-		return tx.Create(&w).Error
+		if txErr := tx.Create(&w).Error; txErr != nil {
+			l.Errorf("Failed to create withdrawal for user %d: %v", ctxUser.Id, txErr)
+			return errors.Wrapf(xerr.NewErrCode(xerr.DatabaseInsertError), "Failed to create withdrawal for user %d: %v", ctxUser.Id, txErr)
+		}
+		return nil
 	})
 	if err != nil {
-		l.Errorf("Failed to create withdrawal for user %d: %v", u.Id, err)
-		return nil, errors.Wrapf(xerr.NewErrCode(xerr.DatabaseInsertError), "Failed to create withdrawal for user %d: %v", u.Id, err)
+		return nil, err
 	}
 
 	return &types.WithdrawalLog{
 		Id:        w.Id,
-		UserId:    u.Id,
+		UserId:    ctxUser.Id,
 		Amount:    req.Amount,
 		Content:   req.Content,
 		Status:    user.WithdrawalStatusPending,