feat(member): implement member center management module

src/Application/TakeoutSaaS.Application/App/Members/Queries/GetMemberTierDetailQuery.cs

@@ -0,0 +1,15 @@
+using MediatR;
+using TakeoutSaaS.Application.App.Members.Dto;
+
+namespace TakeoutSaaS.Application.App.Members.Queries;
+
+/// <summary>
+/// 会员等级详情查询。
+/// </summary>
+public sealed class GetMemberTierDetailQuery : IRequest<MemberTierDetailDto>
+{
+    /// <summary>
+    /// 等级标识（为空时返回新增默认模板）。
+    /// </summary>
+    public long? TierId { get; init; }
+}