feat: 添加用户权限洞察查询与示例

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

@@ -0,0 +1,42 @@
+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>
+/// 按用户 ID 获取权限概览处理器。
+/// </summary>
+public sealed class GetUserPermissionsQueryHandler(
+    IIdentityUserRepository identityUserRepository,
+    ITenantProvider tenantProvider)
+    : IRequestHandler<GetUserPermissionsQuery, UserPermissionDto?>
+{
+    private readonly IIdentityUserRepository _identityUserRepository = identityUserRepository;
+    private readonly ITenantProvider _tenantProvider = tenantProvider;
+
+    /// <inheritdoc />
+    public async Task<UserPermissionDto?> Handle(GetUserPermissionsQuery request, CancellationToken cancellationToken)
+    {
+        var tenantId = _tenantProvider.GetCurrentTenantId();
+        var user = await _identityUserRepository.FindByIdAsync(request.UserId, cancellationToken);
+        if (user == null || user.TenantId != tenantId)
+        {
+            return null;
+        }
+
+        return new UserPermissionDto
+        {
+            UserId = user.Id,
+            TenantId = user.TenantId,
+            MerchantId = user.MerchantId,
+            Account = user.Account,
+            DisplayName = user.DisplayName,
+            Roles = user.Roles,
+            Permissions = user.Permissions,
+            CreatedAt = user.CreatedAt
+        };
+    }
+}