feat: add permission hierarchy tree

src/Application/TakeoutSaaS.Application/Identity/Queries/PermissionTreeQuery.cs

@@ -0,0 +1,15 @@
+using MediatR;
+using TakeoutSaaS.Application.Identity.Contracts;
+
+namespace TakeoutSaaS.Application.Identity.Queries;
+
+/// <summary>
+/// 权限树查询。
+/// </summary>
+public sealed class PermissionTreeQuery : IRequest<IReadOnlyList<PermissionTreeDto>>
+{
+    /// <summary>
+    /// 关键字（可选）。
+    /// </summary>
+    public string? Keyword { get; init; }
+}