feat: Excel 导入按列位置读取，IoT 卡导入支持卡业务类型

- 重写 parseCardRows：移除列名识别，固定跳过第1行表头，按 col0=ICCID、
  col1=MSISDN、col2=VirtualNo 取值，VirtualNo 升级为必填字段
- 重写 ParseDeviceExcel：移除 buildDeviceColumnIndex，IMEI 调整至第5列
  新增 MaxSimSlots 范围校验 [1,4]，整行为空时不计入 total
- 删除 findCardColumns 和 buildDeviceColumnIndex 两个冗余函数
- ImportIotCardRequest 新增 card_category 字段（normal/industry，默认 normal）
- IotCardImportTask model 新增 card_category 字段
- 迁移 000111：tb_iot_card_import_task 新增 card_category 列
- CreateImportTask 将 req.CardCategory 写入任务，空串兜底 normal
- processBatch 改用 task.CardCategory 替代写死的 CardCategoryNormal
- ImportTaskResponse 新增 card_category 字段返回

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

internal/service/iot_card_import/service.go

@@ -70,15 +70,21 @@ func (s *Service) CreateImportTask(ctx context.Context, req *dto.ImportIotCardRe
 	taskNo := s.importTaskStore.GenerateTaskNo(ctx)
 	fileName := filepath.Base(req.FileKey)
 
+	cardCategory := req.CardCategory
+	if cardCategory == "" {
+		cardCategory = constants.CardCategoryNormal
+	}
+
 	task := &model.IotCardImportTask{
-		TaskNo:      taskNo,
-		Status:      model.ImportTaskStatusPending,
-		CarrierID:   req.CarrierID,
-		CarrierType: carrier.CarrierType,
-		CarrierName: carrier.CarrierName,
-		BatchNo:     req.BatchNo,
-		FileName:    fileName,
-		StorageKey:  req.FileKey,
+		TaskNo:       taskNo,
+		Status:       model.ImportTaskStatusPending,
+		CarrierID:    req.CarrierID,
+		CarrierType:  carrier.CarrierType,
+		CarrierName:  carrier.CarrierName,
+		BatchNo:      req.BatchNo,
+		FileName:     fileName,
+		StorageKey:   req.FileKey,
+		CardCategory: cardCategory,
 	}
 	task.Creator = userID
 	task.Updater = userID
@@ -202,6 +208,7 @@ func (s *Service) toTaskResponse(task *model.IotCardImportTask) *dto.ImportTaskR
 		CarrierType:  task.CarrierType,
 		CarrierName:  task.CarrierName,
 		BatchNo:      task.BatchNo,
+		CardCategory: task.CardCategory,
 		FileName:     task.FileName,
 		TotalCount:   task.TotalCount,
 		SuccessCount: task.SuccessCount,