feat: 给 PackageUsage 添加 package_name 快照字段，修复企业卡列表 carrier_name/package_name 为空问题

- 迁移 000099：tb_package_usage 新增 package_name 列，回填历史数据
- PackageUsage model 添加 PackageName 字段（与 DataResetCycle 保持一致的快照设计）
- 4 处 PackageUsage 创建点补充 PackageName 快照（order/service.go + auto_purchase.go）
- EnterpriseCard ListCards：carrier_name 直接取 card.CarrierName，package_name 通过
  DISTINCT ON 批量查当前生效主套餐，单次查询覆盖整页，无 N+1

internal/service/enterprise_card/service.go

@@ -288,6 +288,13 @@ func (s *Service) ListCards(ctx context.Context, enterpriseID uint, req *dto.Ent
 		return nil, errors.Wrap(errors.CodeInternalError, err, "查询卡列表失败")
 	}
 
+	// 批量查询各卡当前生效的主套餐名称（取 package_name 快照，避免 JOIN tb_package）
+	pageCardIDs := make([]uint, 0, len(cards))
+	for _, card := range cards {
+		pageCardIDs = append(pageCardIDs, card.ID)
+	}
+	packageNameMap := s.buildPackageNameMap(ctx, pageCardIDs)
+
 	items := make([]dto.EnterpriseCardItem, 0, len(cards))
 	for _, card := range cards {
 		items = append(items, dto.EnterpriseCardItem{
@@ -295,6 +302,8 @@ func (s *Service) ListCards(ctx context.Context, enterpriseID uint, req *dto.Ent
 			ICCID:             card.ICCID,
 			MSISDN:            card.MSISDN,
 			CarrierID:         card.CarrierID,
+			CarrierName:       card.CarrierName,
+			PackageName:       packageNameMap[card.ID],
 			Status:            card.Status,
 			StatusName:        getCardStatusName(card.Status),
 			NetworkStatus:     card.NetworkStatus,
@@ -310,6 +319,36 @@ func (s *Service) ListCards(ctx context.Context, enterpriseID uint, req *dto.Ent
 	}, nil
 }
 
+// buildPackageNameMap 批量查询卡列表当前生效主套餐名称，返回 map[iotCardID]packageName
+func (s *Service) buildPackageNameMap(ctx context.Context, cardIDs []uint) map[uint]string {
+	result := make(map[uint]string, len(cardIDs))
+	if len(cardIDs) == 0 {
+		return result
+	}
+
+	type usageRow struct {
+		IotCardID   uint   `gorm:"column:iot_card_id"`
+		PackageName string `gorm:"column:package_name"`
+	}
+
+	// 每张卡取优先级最低（数字最小）的生效中主套餐，使用 DISTINCT ON 保证每卡仅一条
+	var rows []usageRow
+	s.db.WithContext(ctx).Raw(`
+		SELECT DISTINCT ON (iot_card_id) iot_card_id, package_name
+		FROM tb_package_usage
+		WHERE iot_card_id IN ?
+		  AND status = 1
+		  AND master_usage_id IS NULL
+		  AND deleted_at IS NULL
+		ORDER BY iot_card_id, priority ASC
+	`, cardIDs).Scan(&rows)
+
+	for _, row := range rows {
+		result[row.IotCardID] = row.PackageName
+	}
+	return result
+}
+
 func (s *Service) SuspendCard(ctx context.Context, enterpriseID, cardID uint) error {
 	return s.updateCardNetworkStatus(ctx, enterpriseID, cardID, 0)
 }