feat(billing): 新增逾期账单自动标记定时任务

1. 新增Hangfire定时任务BillingOverdueProcessJob
2. 修复逾期账单查询条件过宽问题
3. 默认每10分钟执行一次逾期检查

src/Application/TakeoutSaaS.Application/App/Billings/Handlers/ProcessOverdueBillingsCommandHandler.cs

@@ -1,6 +1,6 @@
 using MediatR;
 using TakeoutSaaS.Application.App.Billings.Commands;
-using TakeoutSaaS.Domain.Tenants.Repositories;
+using TakeoutSaaS.Domain.Tenants.Services;
 
 namespace TakeoutSaaS.Application.App.Billings.Handlers;
 
@@ -8,42 +8,13 @@ namespace TakeoutSaaS.Application.App.Billings.Handlers;
 /// 处理逾期账单命令处理器（后台任务）。
 /// </summary>
 public sealed class ProcessOverdueBillingsCommandHandler(
-    ITenantBillingRepository billingRepository)
+    IBillingDomainService billingDomainService)
     : IRequestHandler<ProcessOverdueBillingsCommand, int>
 {
     /// <inheritdoc />
     public async Task<int> Handle(ProcessOverdueBillingsCommand request, CancellationToken cancellationToken)
     {
-        // 1. 查询逾期账单（到期日已过且未支付）
-        var overdueBillings = await billingRepository.GetOverdueBillingsAsync(cancellationToken);
-        if (overdueBillings.Count == 0)
-        {
-            return 0;
-        }
-
-        // 2. (空行后) 标记为逾期并更新通知时间
-        var now = DateTime.UtcNow;
-        var updatedCount = 0;
-        foreach (var billing in overdueBillings)
-        {
-            var before = billing.Status;
-            billing.MarkAsOverdue();
-
-            if (before != billing.Status)
-            {
-                billing.OverdueNotifiedAt ??= now;
-                await billingRepository.UpdateAsync(billing, cancellationToken);
-                updatedCount++;
-            }
-        }
-
-        // 3. (空行后) 持久化
-        if (updatedCount > 0)
-        {
-            await billingRepository.SaveChangesAsync(cancellationToken);
-        }
-
-        return updatedCount;
+        // 1. 委托领域服务执行逾期账单处理（Pending && DueDate < Now -> Overdue）
+        return await billingDomainService.ProcessOverdueBillingsAsync(cancellationToken);
     }
 }
-