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/enterprise_card/service.go

@@ -97,7 +97,7 @@ func (s *Service) AllocateCardsPreview(ctx context.Context, enterpriseID uint, r
 			IotCardID:  card.ID,
 			MSISDN:     card.MSISDN,
 			CarrierID:  card.CarrierID,
-			StatusName: getCardStatusName(card.Status),
+			StatusName: constants.GetIotCardStatusName(card.Status),
 		})
 	}
 
@@ -305,9 +305,9 @@ func (s *Service) ListCards(ctx context.Context, enterpriseID uint, req *dto.Ent
 			CarrierName:       card.CarrierName,
 			PackageName:       packageNameMap[card.ID],
 			Status:            card.Status,
-			StatusName:        getCardStatusName(card.Status),
+			StatusName:        constants.GetIotCardStatusName(card.Status),
 			NetworkStatus:     card.NetworkStatus,
-			NetworkStatusName: getNetworkStatusName(card.NetworkStatus),
+			NetworkStatusName: constants.GetNetworkStatusName(card.NetworkStatus),
 		})
 	}
 
@@ -377,25 +377,3 @@ func (s *Service) updateCardNetworkStatus(ctx context.Context, enterpriseID, car
 		Where("id = ?", cardID).
 		Update("network_status", networkStatus).Error
 }
-
-func getCardStatusName(status int) string {
-	switch status {
-	case 1:
-		return "在库"
-	case 2:
-		return "已分销"
-	case 3:
-		return "已激活"
-	case 4:
-		return "已停用"
-	default:
-		return "未知"
-	}
-}
-
-func getNetworkStatusName(status int) string {
-	if status == 1 {
-		return "开机"
-	}
-	return "停机"
-}