fix(poll): Series 删除前检查关联套餐 POLL-04

- package_store.go 新增 CountBySeriesID 方法，统计指定系列下的活跃套餐数量
- package_series/service.go Service 注入 packageStore 字段，Delete 前调用 CountBySeriesID 检查
- bootstrap/services.go 更新 PackageSeries 服务初始化，传入 PackageStore

internal/service/package_series/service.go

@@ -2,6 +2,7 @@ package package_series
 
 import (
 	"context"
+	"fmt"
 	"time"
 
 	"gorm.io/gorm"
@@ -15,15 +16,19 @@ import (
 	"github.com/break/junhong_cmp_fiber/pkg/middleware"
 )
 
+// Service 套餐系列业务服务
 type Service struct {
 	packageSeriesStore        *postgres.PackageSeriesStore
 	shopSeriesAllocationStore *postgres.ShopSeriesAllocationStore
+	packageStore              *postgres.PackageStore
 }
 
-func New(packageSeriesStore *postgres.PackageSeriesStore, shopSeriesAllocationStore *postgres.ShopSeriesAllocationStore) *Service {
+// New 创建套餐系列服务实例
+func New(packageSeriesStore *postgres.PackageSeriesStore, shopSeriesAllocationStore *postgres.ShopSeriesAllocationStore, packageStore *postgres.PackageStore) *Service {
 	return &Service{
 		packageSeriesStore:        packageSeriesStore,
 		shopSeriesAllocationStore: shopSeriesAllocationStore,
+		packageStore:              packageStore,
 	}
 }
 
@@ -139,6 +144,14 @@ func (s *Service) Delete(ctx context.Context, id uint) error {
 		return errors.Wrap(errors.CodeInternalError, err, "获取套餐系列失败")
 	}
 
+	count, err := s.packageStore.CountBySeriesID(ctx, id)
+	if err != nil {
+		return err
+	}
+	if count > 0 {
+		return errors.New(errors.CodeInvalidParam, fmt.Sprintf("该系列下有 %d 个关联套餐，请先处理后再删除", count))
+	}
+
 	if err := s.packageSeriesStore.Delete(ctx, id); err != nil {
 		return errors.Wrap(errors.CodeInternalError, err, "删除套餐系列失败")
 	}