feat: 添加支付回调链路（支付成功 → 订单状态流转 → SignalR 推送）

- 新增 ProcessPaymentCallbackCommand + Handler（幂等处理）
- 丰富 PaymentSucceededEvent（StoreId、OrderNo、Channel 等字段）
- 新增 PaymentSucceededConsumer（支付成功 → NewOrder 推送）
- 新增 PaymentCallbackController（微信/支付宝预留 + 内部测试端点）
- Program.cs 注册 PaymentSucceededConsumer

src/Api/TakeoutSaaS.TenantApi/Consumers/PaymentSucceededConsumer.cs

@@ -0,0 +1,34 @@
+using MassTransit;
+using Microsoft.AspNetCore.SignalR;
+using TakeoutSaaS.Application.Messaging.Events;
+using TakeoutSaaS.TenantApi.Hubs;
+
+namespace TakeoutSaaS.TenantApi.Consumers;
+
+/// <summary>
+/// 支付成功事件消费者 — 推送新订单到看板。
+/// </summary>
+public sealed class PaymentSucceededConsumer(IHubContext<OrderBoardHub> hubContext)
+    : IConsumer<PaymentSucceededEvent>
+{
+    /// <inheritdoc />
+    public async Task Consume(ConsumeContext<PaymentSucceededEvent> context)
+    {
+        var e = context.Message;
+        var group = $"store:{e.TenantId}:{e.StoreId}";
+
+        // 1. 支付成功 = 新订单出现在待接单列，推送 NewOrder
+        await hubContext.Clients.Group(group).SendAsync("NewOrder", new
+        {
+            e.OrderId,
+            e.OrderNo,
+            e.Amount,
+            e.StoreId,
+            e.Channel,
+            e.DeliveryType,
+            e.CustomerName,
+            e.ItemsSummary,
+            e.PaidAt
+        }, context.CancellationToken);
+    }
+}

src/Api/TakeoutSaaS.TenantApi/Controllers/PaymentCallbackController.cs

@@ -0,0 +1,99 @@
+using Asp.Versioning;
+using MediatR;
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using TakeoutSaaS.Application.App.Payments.Commands;
+using TakeoutSaaS.Application.App.Stores.Services;
+using TakeoutSaaS.Domain.Payments.Enums;
+using TakeoutSaaS.Shared.Abstractions.Results;
+using TakeoutSaaS.Shared.Web.Api;
+
+namespace TakeoutSaaS.TenantApi.Controllers;
+
+/// <summary>
+/// 支付回调接口。
+/// </summary>
+[ApiVersion("1.0")]
+[Route("api/tenant/v{version:apiVersion}/payment/callback")]
+public sealed class PaymentCallbackController(
+    IMediator mediator,
+    StoreContextService storeContextService) : BaseApiController
+{
+    /// <summary>
+    /// 微信支付回调（预留，签名验证后续接入 SDK）。
+    /// </summary>
+    [HttpPost("wechat")]
+    [AllowAnonymous]
+    public async Task<IActionResult> WeChatCallback(CancellationToken cancellationToken)
+    {
+        // TODO: 接入微信支付 V3 SDK 后实现签名验证与报文解析
+        return Ok(new { code = "SUCCESS", message = "成功" });
+    }
+
+    /// <summary>
+    /// 支付宝回调（预留，签名验证后续接入 SDK）。
+    /// </summary>
+    [HttpPost("alipay")]
+    [AllowAnonymous]
+    public async Task<IActionResult> AlipayCallback(CancellationToken cancellationToken)
+    {
+        // TODO: 接入支付宝 RSA2 SDK 后实现签名验证与报文解析
+        return Ok("success");
+    }
+
+    /// <summary>
+    /// 内部模拟支付回调（仅开发环境）。
+    /// </summary>
+    [HttpPost("internal")]
+    [Authorize]
+    public async Task<ApiResponse<bool>> InternalCallback(
+        [FromBody] InternalPaymentCallbackRequest request,
+        CancellationToken cancellationToken)
+    {
+        var (_, tenantId, _) = storeContextService.GetRequiredContext();
+
+        var result = await mediator.Send(new ProcessPaymentCallbackCommand
+        {
+            OrderNo = request.OrderNo,
+            ChannelTransactionId = request.TransactionId ?? $"internal-{Guid.NewGuid():N}",
+            Method = request.Method ?? PaymentMethod.WeChatPay,
+            Amount = request.Amount,
+            PaidAt = request.PaidAt ?? DateTime.UtcNow,
+            TenantId = tenantId,
+            RawPayload = "internal-test"
+        }, cancellationToken);
+
+        return ApiResponse<bool>.Ok(result);
+    }
+}
+
+/// <summary>
+/// 内部模拟支付回调请求体。
+/// </summary>
+public sealed record InternalPaymentCallbackRequest
+{
+    /// <summary>
+    /// 订单号。
+    /// </summary>
+    public required string OrderNo { get; init; }
+
+    /// <summary>
+    /// 支付金额。
+    /// </summary>
+    public required decimal Amount { get; init; }
+
+    /// <summary>
+    /// 支付流水号（可选）。
+    /// </summary>
+    public string? TransactionId { get; init; }
+
+    /// <summary>
+    /// 支付方式（可选，默认微信）。
+    /// </summary>
+    public PaymentMethod? Method { get; init; }
+
+    /// <summary>
+    /// 支付时间（可选，默认当前时间）。
+    /// </summary>
+    public DateTime? PaidAt { get; init; }
+}

src/Application/TakeoutSaaS.Application/App/Payments/Commands/ProcessPaymentCallbackCommand.cs

@@ -0,0 +1,45 @@
+using MediatR;
+using TakeoutSaaS.Domain.Payments.Enums;
+
+namespace TakeoutSaaS.Application.App.Payments.Commands;
+
+/// <summary>
+/// 支付回调处理命令。
+/// </summary>
+public sealed record ProcessPaymentCallbackCommand : IRequest<bool>
+{
+    /// <summary>
+    /// 商户订单号。
+    /// </summary>
+    public required string OrderNo { get; init; }
+
+    /// <summary>
+    /// 第三方支付流水号。
+    /// </summary>
+    public required string ChannelTransactionId { get; init; }
+
+    /// <summary>
+    /// 支付方式。
+    /// </summary>
+    public required PaymentMethod Method { get; init; }
+
+    /// <summary>
+    /// 实付金额。
+    /// </summary>
+    public required decimal Amount { get; init; }
+
+    /// <summary>
+    /// 支付时间。
+    /// </summary>
+    public required DateTime PaidAt { get; init; }
+
+    /// <summary>
+    /// 租户标识。
+    /// </summary>
+    public required long TenantId { get; init; }
+
+    /// <summary>
+    /// 原始回调报文（留存）。
+    /// </summary>
+    public string? RawPayload { get; init; }
+}

src/Application/TakeoutSaaS.Application/App/Payments/Handlers/ProcessPaymentCallbackCommandHandler.cs

@@ -0,0 +1,132 @@
+using MediatR;
+using Microsoft.Extensions.Logging;
+using TakeoutSaaS.Application.App.Payments.Commands;
+using TakeoutSaaS.Application.Messaging;
+using TakeoutSaaS.Application.Messaging.Abstractions;
+using TakeoutSaaS.Application.Messaging.Events;
+using TakeoutSaaS.Domain.Orders.Entities;
+using TakeoutSaaS.Domain.Orders.Enums;
+using TakeoutSaaS.Domain.Orders.Repositories;
+using TakeoutSaaS.Domain.Payments.Entities;
+using TakeoutSaaS.Domain.Payments.Enums;
+using TakeoutSaaS.Domain.Payments.Repositories;
+using TakeoutSaaS.Shared.Abstractions.Constants;
+using TakeoutSaaS.Shared.Abstractions.Exceptions;
+using TakeoutSaaS.Shared.Abstractions.Ids;
+
+namespace TakeoutSaaS.Application.App.Payments.Handlers;
+
+/// <summary>
+/// 支付回调处理器。
+/// </summary>
+public sealed class ProcessPaymentCallbackCommandHandler(
+    IOrderRepository orderRepository,
+    IPaymentRepository paymentRepository,
+    IEventPublisher eventPublisher,
+    IIdGenerator idGenerator,
+    ILogger<ProcessPaymentCallbackCommandHandler> logger)
+    : IRequestHandler<ProcessPaymentCallbackCommand, bool>
+{
+    /// <inheritdoc />
+    public async Task<bool> Handle(ProcessPaymentCallbackCommand request, CancellationToken cancellationToken)
+    {
+        // 1. 通过 OrderNo 查找订单
+        var order = await orderRepository.FindByOrderNoAsync(request.OrderNo, request.TenantId, cancellationToken)
+            ?? throw new BusinessException(ErrorCodes.NotFound, "订单不存在");
+
+        // 2. 幂等检查：已支付则直接返回
+        if (order.PaymentStatus == PaymentStatus.Paid)
+        {
+            logger.LogWarning("订单 {OrderNo} 重复支付回调，已忽略", request.OrderNo);
+            return true;
+        }
+
+        // 3. 校验订单状态
+        if (order.Status != OrderStatus.PendingPayment)
+        {
+            throw new BusinessException(ErrorCodes.BadRequest, $"订单状态 {order.Status} 不允许支付");
+        }
+
+        // 4. 创建支付记录
+        var paymentRecord = new PaymentRecord
+        {
+            Id = idGenerator.NextId(),
+            TenantId = order.TenantId,
+            OrderId = order.Id,
+            Method = request.Method,
+            Status = PaymentStatus.Paid,
+            Amount = request.Amount,
+            ChannelTransactionId = request.ChannelTransactionId,
+            PaidAt = request.PaidAt,
+            Payload = request.RawPayload
+        };
+        await paymentRepository.AddPaymentAsync(paymentRecord, cancellationToken);
+
+        // 5. 更新订单支付状态与订单状态
+        order.PaymentStatus = PaymentStatus.Paid;
+        order.PaidAmount = request.Amount;
+        order.PaidAt = request.PaidAt;
+        order.Status = OrderStatus.AwaitingPreparation;
+        await orderRepository.UpdateOrderAsync(order, cancellationToken);
+
+        // 6. 写入状态流转记录
+        var history = new OrderStatusHistory
+        {
+            Id = idGenerator.NextId(),
+            OrderId = order.Id,
+            TenantId = order.TenantId,
+            Status = OrderStatus.AwaitingPreparation,
+            Notes = "支付成功，进入待接单",
+            OccurredAt = request.PaidAt
+        };
+        await orderRepository.AddStatusHistoryAsync(history, cancellationToken);
+
+        // 7. 持久化
+        await orderRepository.SaveChangesAsync(cancellationToken);
+
+        // 8. 构建商品摘要
+        var items = await orderRepository.GetItemsAsync(order.Id, order.TenantId, cancellationToken);
+        var itemsSummary = items.Count > 0
+            ? string.Join("、", items.Take(3).Select(x => x.ProductName))
+              + (items.Count > 3 ? $" 等{items.Count}件" : string.Empty)
+            : string.Empty;
+
+        // 9. 发布支付成功事件
+        await eventPublisher.PublishAsync(EventRoutingKeys.PaymentSucceeded, new PaymentSucceededEvent
+        {
+            OrderId = order.Id,
+            PaymentNo = paymentRecord.TradeNo ?? string.Empty,
+            Amount = request.Amount,
+            TenantId = order.TenantId,
+            StoreId = order.StoreId,
+            OrderNo = order.OrderNo,
+            Channel = (int)order.Channel,
+            DeliveryType = (int)order.DeliveryType,
+            CustomerName = order.CustomerName,
+            ItemsSummary = itemsSummary,
+            PaidAt = request.PaidAt
+        }, cancellationToken);
+
+        // 10. 发布订单状态变更事件（触发 SignalR 推送）
+        await eventPublisher.PublishAsync(EventRoutingKeys.OrderStatusChanged, new OrderStatusChangedEvent
+        {
+            OrderId = order.Id,
+            OrderNo = order.OrderNo,
+            TenantId = order.TenantId,
+            StoreId = order.StoreId,
+            OldStatus = (int)OrderStatus.PendingPayment,
+            NewStatus = (int)OrderStatus.AwaitingPreparation,
+            Channel = (int)order.Channel,
+            DeliveryType = (int)order.DeliveryType,
+            CustomerName = order.CustomerName,
+            ItemsSummary = itemsSummary,
+            PaidAmount = request.Amount,
+            OccurredAt = request.PaidAt
+        }, cancellationToken);
+
+        // 11. 记录日志
+        logger.LogInformation("支付回调成功 {OrderNo}，金额 {Amount}", request.OrderNo, request.Amount);
+
+        return true;
+    }
+}

src/Application/TakeoutSaaS.Application/Messaging/Events/PaymentSucceededEvent.cs

@@ -25,6 +25,36 @@ public sealed class PaymentSucceededEvent
     /// </summary>
     public long TenantId { get; init; }
 
+    /// <summary>
+    /// 门店标识。
+    /// </summary>
+    public long StoreId { get; init; }
+
+    /// <summary>
+    /// 订单编号。
+    /// </summary>
+    public string OrderNo { get; init; } = string.Empty;
+
+    /// <summary>
+    /// 下单渠道。
+    /// </summary>
+    public int Channel { get; init; }
+
+    /// <summary>
+    /// 履约类型。
+    /// </summary>
+    public int DeliveryType { get; init; }
+
+    /// <summary>
+    /// 顾客姓名。
+    /// </summary>
+    public string? CustomerName { get; init; }
+
+    /// <summary>
+    /// 商品摘要。
+    /// </summary>
+    public string? ItemsSummary { get; init; }
+
     /// <summary>
     /// 支付时间（UTC）。
     /// </summary>