feat: 套餐管理与配额校验能力

src/Application/TakeoutSaaS.Application/App/Tenants/Handlers/GetTenantPackageByIdQueryHandler.cs

@@ -0,0 +1,20 @@
+using MediatR;
+using TakeoutSaaS.Application.App.Tenants.Dto;
+using TakeoutSaaS.Application.App.Tenants.Queries;
+using TakeoutSaaS.Domain.Tenants.Repositories;
+
+namespace TakeoutSaaS.Application.App.Tenants.Handlers;
+
+/// <summary>
+/// 套餐详情查询处理器。
+/// </summary>
+public sealed class GetTenantPackageByIdQueryHandler(ITenantPackageRepository packageRepository)
+    : IRequestHandler<GetTenantPackageByIdQuery, TenantPackageDto?>
+{
+    /// <inheritdoc />
+    public async Task<TenantPackageDto?> Handle(GetTenantPackageByIdQuery request, CancellationToken cancellationToken)
+    {
+        var package = await packageRepository.FindByIdAsync(request.TenantPackageId, cancellationToken);
+        return package?.ToDto();
+    }
+}