feat: 实现订阅自动化定时任务系统

新增定时任务 (Scheduler Module):
- SubscriptionAutoRenewalJob: 自动续费账单生成
- SubscriptionRenewalReminderJob: 续费提醒发送 (7/3/1天)
- SubscriptionExpiryCheckJob: 到期检查与宽限期处理

新增 Command/Handler:
- ProcessAutoRenewalCommand: 处理自动续费逻辑
- ProcessRenewalRemindersCommand: 处理续费提醒逻辑
- ProcessSubscriptionExpiryCommand: 处理订阅到期逻辑

配置项 (SubscriptionAutomationOptions):
- AutoRenewalDaysBeforeExpiry: 到期前N天生成续费账单
- ReminderDaysBeforeExpiry: 提醒天数数组
- GracePeriodDays: 宽限期天数
- 各任务执行小时配置

Repository 增强:
- ISubscriptionRepository: 新增自动化查询方法
- ITenantBillingRepository: 新增账单创建方法
- ITenantNotificationRepository: 新增通知创建方法

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/Modules/TakeoutSaaS.Module.Scheduler/Jobs/SubscriptionRenewalReminderJob.cs

@@ -0,0 +1,35 @@
+using MediatR;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+using TakeoutSaaS.Application.App.Subscriptions.Commands;
+using TakeoutSaaS.Module.Scheduler.Options;
+
+namespace TakeoutSaaS.Module.Scheduler.Jobs;
+
+/// <summary>
+/// 订阅续费提醒任务：到期前 7/3/1 天发送站内提醒。
+/// </summary>
+public sealed class SubscriptionRenewalReminderJob(
+    IMediator mediator,
+    IOptionsMonitor<SubscriptionAutomationOptions> optionsMonitor,
+    ILogger<SubscriptionRenewalReminderJob> logger)
+{
+    /// <summary>
+    /// 执行续费提醒扫描与发送。
+    /// </summary>
+    public async Task ExecuteAsync()
+    {
+        // 1. 读取配置并执行续费提醒
+        var options = optionsMonitor.CurrentValue;
+        var result = await mediator.Send(new ProcessRenewalRemindersCommand
+        {
+            ReminderDaysBeforeExpiry = options.ReminderDaysBeforeExpiry
+        });
+
+        // 2. 记录执行结果
+        logger.LogInformation(
+            "定时任务：续费提醒处理完成，候选 {CandidateCount}，创建 {CreatedReminderCount}",
+            result.CandidateCount,
+            result.CreatedReminderCount);
+    }
+}