refactor: 一次性佣金配置从套餐级别提升到系列级别

主要变更:
- 新增 tb_shop_series_allocation 表，存储系列级别的一次性佣金配置
- ShopPackageAllocation 移除 one_time_commission_amount 字段
- PackageSeries 新增 enable_one_time_commission 字段控制是否启用一次性佣金
- 新增 /api/admin/shop-series-allocations CRUD 接口
- 佣金计算逻辑改为从 ShopSeriesAllocation 获取一次性佣金金额
- 删除废弃的 ShopSeriesOneTimeCommissionTier 模型
- OpenAPI Tag '系列分配' 和 '单套餐分配' 合并为 '套餐分配'

迁移脚本:
- 000042: 重构佣金套餐模型
- 000043: 简化佣金分配
- 000044: 一次性佣金分配重构
- 000045: PackageSeries 添加 enable_one_time_commission 字段

测试:
- 新增验收测试 (shop_series_allocation, commission_calculation)
- 新增流程测试 (one_time_commission_chain)
- 删除过时的单元测试（已被验收测试覆盖）

internal/service/shop_package_allocation/service.go

@@ -20,6 +20,7 @@ type Service struct {
 	priceHistoryStore      *postgres.ShopPackageAllocationPriceHistoryStore
 	shopStore              *postgres.ShopStore
 	packageStore           *postgres.PackageStore
+	packageSeriesStore     *postgres.PackageSeriesStore
 }
 
 func New(
@@ -28,6 +29,7 @@ func New(
 	priceHistoryStore *postgres.ShopPackageAllocationPriceHistoryStore,
 	shopStore *postgres.ShopStore,
 	packageStore *postgres.PackageStore,
+	packageSeriesStore *postgres.PackageSeriesStore,
 ) *Service {
 	return &Service{
 		packageAllocationStore: packageAllocationStore,
@@ -35,6 +37,7 @@ func New(
 		priceHistoryStore:      priceHistoryStore,
 		shopStore:              shopStore,
 		packageStore:           packageStore,
+		packageSeriesStore:     packageSeriesStore,
 	}
 }
 
@@ -73,25 +76,26 @@ func (s *Service) Create(ctx context.Context, req *dto.CreateShopPackageAllocati
 		return nil, errors.Wrap(errors.CodeInternalError, err, "获取套餐失败")
 	}
 
+	existing, _ := s.packageAllocationStore.GetByShopAndPackage(ctx, req.ShopID, req.PackageID)
+	if existing != nil {
+		return nil, errors.New(errors.CodeConflict, "该店铺已有此套餐的分配配置")
+	}
+
 	seriesAllocation, err := s.seriesAllocationStore.GetByShopAndSeries(ctx, req.ShopID, pkg.SeriesID)
 	if err != nil {
 		if err == gorm.ErrRecordNotFound {
-			return nil, errors.New(errors.CodeForbidden, "该套餐的系列未分配给此店铺")
+			return nil, errors.New(errors.CodeInvalidParam, "请先分配该套餐所属的系列")
 		}
 		return nil, errors.Wrap(errors.CodeInternalError, err, "获取系列分配失败")
 	}
 
-	existing, _ := s.packageAllocationStore.GetByShopAndPackage(ctx, req.ShopID, req.PackageID)
-	if existing != nil {
-		return nil, errors.New(errors.CodeConflict, "该店铺已有此套餐的覆盖配置")
-	}
-
 	allocation := &model.ShopPackageAllocation{
-		ShopID:       req.ShopID,
-		PackageID:    req.PackageID,
-		AllocationID: seriesAllocation.ID,
-		CostPrice:    req.CostPrice,
-		Status:       constants.StatusEnabled,
+		ShopID:             req.ShopID,
+		PackageID:          req.PackageID,
+		AllocatorShopID:    allocatorShopID,
+		CostPrice:          req.CostPrice,
+		SeriesAllocationID: &seriesAllocation.ID,
+		Status:             constants.StatusEnabled,
 	}
 	allocation.Creator = currentUserID
 
@@ -204,6 +208,12 @@ func (s *Service) List(ctx context.Context, req *dto.ShopPackageAllocationListRe
 	if req.PackageID != nil {
 		filters["package_id"] = *req.PackageID
 	}
+	if req.SeriesAllocationID != nil {
+		filters["series_allocation_id"] = *req.SeriesAllocationID
+	}
+	if req.AllocatorShopID != nil {
+		filters["allocator_shop_id"] = *req.AllocatorShopID
+	}
 	if req.Status != nil {
 		filters["status"] = *req.Status
 	}
@@ -258,19 +268,44 @@ func (s *Service) UpdateStatus(ctx context.Context, id uint, status int) error {
 }
 
 func (s *Service) buildResponse(ctx context.Context, a *model.ShopPackageAllocation, shopName, packageName, packageCode string) (*dto.ShopPackageAllocationResponse, error) {
+	var seriesID uint
+	seriesName := ""
+
+	pkg, _ := s.packageStore.GetByID(ctx, a.PackageID)
+	if pkg != nil {
+		seriesID = pkg.SeriesID
+		series, _ := s.packageSeriesStore.GetByID(ctx, pkg.SeriesID)
+		if series != nil {
+			seriesName = series.SeriesName
+		}
+	}
+
+	allocatorShopName := ""
+	if a.AllocatorShopID > 0 {
+		allocatorShop, _ := s.shopStore.GetByID(ctx, a.AllocatorShopID)
+		if allocatorShop != nil {
+			allocatorShopName = allocatorShop.ShopName
+		}
+	} else {
+		allocatorShopName = "平台"
+	}
+
 	return &dto.ShopPackageAllocationResponse{
-		ID:                  a.ID,
-		ShopID:              a.ShopID,
-		ShopName:            shopName,
-		PackageID:           a.PackageID,
-		PackageName:         packageName,
-		PackageCode:         packageCode,
-		AllocationID:        a.AllocationID,
-		CostPrice:           a.CostPrice,
-		CalculatedCostPrice: 0,
-		Status:              a.Status,
-		CreatedAt:           a.CreatedAt.Format(time.RFC3339),
-		UpdatedAt:           a.UpdatedAt.Format(time.RFC3339),
+		ID:                 a.ID,
+		ShopID:             a.ShopID,
+		ShopName:           shopName,
+		PackageID:          a.PackageID,
+		PackageName:        packageName,
+		PackageCode:        packageCode,
+		SeriesID:           seriesID,
+		SeriesName:         seriesName,
+		SeriesAllocationID: a.SeriesAllocationID,
+		AllocatorShopID:    a.AllocatorShopID,
+		AllocatorShopName:  allocatorShopName,
+		CostPrice:          a.CostPrice,
+		Status:             a.Status,
+		CreatedAt:          a.CreatedAt.Format(time.RFC3339),
+		UpdatedAt:          a.UpdatedAt.Format(time.RFC3339),
 	}, nil
 }