feat: migrate snowflake ids and refresh migrations

src/Application/TakeoutSaaS.Application/App/Merchants/Handlers/GetMerchantByIdQueryHandler.cs

@@ -0,0 +1,42 @@
+using MediatR;
+using TakeoutSaaS.Application.App.Merchants.Dto;
+using TakeoutSaaS.Application.App.Merchants.Queries;
+using TakeoutSaaS.Domain.Merchants.Repositories;
+using TakeoutSaaS.Shared.Abstractions.Tenancy;
+
+namespace TakeoutSaaS.Application.App.Merchants.Handlers;
+
+/// <summary>
+/// 获取商户详情查询处理器。
+/// </summary>
+public sealed class GetMerchantByIdQueryHandler(IMerchantRepository merchantRepository, ITenantProvider tenantProvider)
+    : IRequestHandler<GetMerchantByIdQuery, MerchantDto?>
+{
+    private readonly IMerchantRepository _merchantRepository = merchantRepository;
+    private readonly ITenantProvider _tenantProvider = tenantProvider;
+
+    /// <inheritdoc />
+    public async Task<MerchantDto?> Handle(GetMerchantByIdQuery request, CancellationToken cancellationToken)
+    {
+        var tenantId = _tenantProvider.GetCurrentTenantId();
+        var merchant = await _merchantRepository.FindByIdAsync(request.MerchantId, tenantId, cancellationToken);
+        if (merchant == null)
+        {
+            return null;
+        }
+
+        return new MerchantDto
+        {
+            Id = merchant.Id,
+            TenantId = merchant.TenantId,
+            BrandName = merchant.BrandName,
+            BrandAlias = merchant.BrandAlias,
+            LogoUrl = merchant.LogoUrl,
+            Category = merchant.Category,
+            ContactPhone = merchant.ContactPhone,
+            ContactEmail = merchant.ContactEmail,
+            Status = merchant.Status,
+            JoinedAt = merchant.JoinedAt
+        };
+    }
+}