feat: 新增RBAC角色模板复制与初始化

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

@@ -0,0 +1,20 @@
+using MediatR;
+using TakeoutSaaS.Application.Identity.Abstractions;
+using TakeoutSaaS.Application.Identity.Contracts;
+using TakeoutSaaS.Application.Identity.Queries;
+
+namespace TakeoutSaaS.Application.Identity.Handlers;
+
+/// <summary>
+/// 角色模板详情查询处理器。
+/// </summary>
+public sealed class GetRoleTemplateQueryHandler(IRoleTemplateProvider roleTemplateProvider)
+    : IRequestHandler<GetRoleTemplateQuery, RoleTemplateDto?>
+{
+    /// <inheritdoc />
+    public Task<RoleTemplateDto?> Handle(GetRoleTemplateQuery request, CancellationToken cancellationToken)
+    {
+        var template = roleTemplateProvider.FindByCode(request.TemplateCode);
+        return Task.FromResult(template is null ? null : TemplateMapper.ToDto(template));
+    }
+}