refactor: 统一状态名称映射为公共函数，清理废弃换卡/商户类型常量和模型

internal/service/agent_recharge/service.go

@@ -469,23 +469,6 @@ func (s *Service) generateRechargeNo() string {
 	return fmt.Sprintf("%s%s%06d", constants.AgentRechargeOrderPrefix, timestamp, randomNum)
 }
 
-func agentRechargeStatusName(status int) string {
-	switch status {
-	case constants.RechargeStatusPending:
-		return "待支付"
-	case constants.RechargeStatusPaid:
-		return "已支付"
-	case constants.RechargeStatusCompleted:
-		return "已完成"
-	case constants.RechargeStatusClosed:
-		return "已关闭"
-	case constants.RechargeStatusRefunded:
-		return "已退款"
-	default:
-		return "未知"
-	}
-}
-
 // toResponse 将模型转换为响应 DTO
 func toResponse(record *model.AgentRechargeRecord, shopName string) *dto.AgentRechargeResponse {
 	resp := &dto.AgentRechargeResponse{
@@ -497,7 +480,7 @@ func toResponse(record *model.AgentRechargeRecord, shopName string) *dto.AgentRe
 		Amount:        record.Amount,
 		PaymentMethod: record.PaymentMethod,
 		Status:        record.Status,
-		StatusName:    agentRechargeStatusName(record.Status),
+		StatusName:    constants.GetRechargeStatusName(record.Status),
 		CreatedAt:     record.CreatedAt.Format("2006-01-02 15:04:05"),
 		UpdatedAt:     record.UpdatedAt.Format("2006-01-02 15:04:05"),
 	}