feat: implement withdrawal improvements P01-P05

- P04: fix Withdrawal.TableName() to return 'withdrawals'
- P03: add WithdrawalStatus* and WithdrawalMethod* constants; replace magic numbers; add CommissionTypeWithdrawCancel=338
- P01: add POST /v1/public/user/withdrawal_cancel to cancel pending withdrawals with ownership check, row lock, commission refund, and audit log
- P02: add method/account/qr_code_url fields to Withdrawal model and API; add input validation (qr_code_url required for Alipay/Wechat, account required for bank)
- P05: add method filter to admin GET /v1/admin/user/withdrawal/list

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

internal/logic/admin/user/getWithdrawalListLogic.go

@@ -42,6 +42,9 @@ func (l *GetWithdrawalListLogic) GetWithdrawalList(req *types.GetWithdrawalListR
 	if req.Status != nil {
 		query = query.Where("status = ?", *req.Status)
 	}
+	if req.Method != nil {
+		query = query.Where("method = ?", *req.Method)
+	}
 
 	var total int64
 	if err := query.Count(&total).Error; err != nil {
@@ -62,6 +65,9 @@ func (l *GetWithdrawalListLogic) GetWithdrawalList(req *types.GetWithdrawalListR
 			Content:   row.Content,
 			Status:    row.Status,
 			Reason:    row.Reason,
+			Method:    row.Method,
+			Account:   row.Account,
+			QrCodeUrl: row.QrCodeUrl,
 			CreatedAt: row.CreatedAt.UnixMilli(),
 			UpdatedAt: row.UpdatedAt.UnixMilli(),
 		})