feat: add admin menu management crud

src/Application/TakeoutSaaS.Application/Identity/Handlers/ListMenusQueryHandler.cs

@@ -0,0 +1,32 @@
+using MediatR;
+using TakeoutSaaS.Application.Identity.Contracts;
+using TakeoutSaaS.Application.Identity.Queries;
+using TakeoutSaaS.Domain.Identity.Repositories;
+using TakeoutSaaS.Shared.Abstractions.Tenancy;
+
+namespace TakeoutSaaS.Application.Identity.Handlers;
+
+/// <summary>
+/// 菜单列表查询处理器。
+/// </summary>
+public sealed class ListMenusQueryHandler(
+    IMenuRepository menuRepository,
+    ITenantProvider tenantProvider)
+    : IRequestHandler<ListMenusQuery, IReadOnlyList<MenuDefinitionDto>>
+{
+    /// <inheritdoc />
+    public async Task<IReadOnlyList<MenuDefinitionDto>> Handle(ListMenusQuery request, CancellationToken cancellationToken)
+    {
+        // 1. 获取租户
+        var tenantId = tenantProvider.GetCurrentTenantId();
+
+        // 2. 查询列表
+        var entities = await menuRepository.GetByTenantAsync(tenantId, cancellationToken);
+
+        // 3. 映射 DTO
+        var items = entities.Select(MenuMapper.ToDto).ToList();
+
+        // 4. 返回结果
+        return items;
+    }
+}