feat(marketing): implement flash sale module api and app layer

src/Domain/TakeoutSaaS.Domain/Products/Repositories/IProductRepository.cs

@@ -140,6 +140,15 @@ public interface IProductRepository
     /// </summary>
     Task<IReadOnlyList<Product>> SearchPickerAsync(long tenantId, long storeId, long? categoryId, string? keyword, int limit, CancellationToken cancellationToken = default);
 
+    /// <summary>
+    /// 按标识批量读取商品。
+    /// </summary>
+    Task<IReadOnlyList<Product>> GetByIdsAsync(
+        long tenantId,
+        long storeId,
+        IReadOnlyCollection<long> productIds,
+        CancellationToken cancellationToken = default);
+
     /// <summary>
     /// 批量更新商品分类。
     /// </summary>