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/Infrastructure/TakeoutSaaS.Infrastructure/App/Repositories/EfSubscriptionRepository.cs

@@ -165,6 +165,88 @@ public sealed class EfSubscriptionRepository(TakeoutAppDbContext dbContext) : IS
             .ToListAsync(cancellationToken);
     }
 
+    /// <inheritdoc />
+    public async Task<IReadOnlyList<AutoRenewalCandidate>> FindAutoRenewalCandidatesAsync(
+        DateTime now,
+        DateTime renewalThreshold,
+        CancellationToken cancellationToken = default)
+    {
+        // 1. 查询开启自动续费且即将到期的活跃订阅
+        var query = dbContext.TenantSubscriptions
+            .Where(s => s.Status == SubscriptionStatus.Active
+                        && s.AutoRenew
+                        && s.EffectiveTo <= renewalThreshold
+                        && s.EffectiveTo > now)
+            .Join(
+                dbContext.TenantPackages,
+                subscription => subscription.TenantPackageId,
+                package => package.Id,
+                (subscription, package) => new AutoRenewalCandidate
+                {
+                    Subscription = subscription,
+                    Package = package
+                });
+
+        // 2. 返回候选列表
+        return await query.ToListAsync(cancellationToken);
+    }
+
+    /// <inheritdoc />
+    public async Task<IReadOnlyList<RenewalReminderCandidate>> FindRenewalReminderCandidatesAsync(
+        DateTime startOfDay,
+        DateTime endOfDay,
+        CancellationToken cancellationToken = default)
+    {
+        // 1. 查询到期落在指定区间的订阅（且未开启自动续费）
+        var query = dbContext.TenantSubscriptions
+            .Where(s => s.Status == SubscriptionStatus.Active
+                        && !s.AutoRenew
+                        && s.EffectiveTo >= startOfDay
+                        && s.EffectiveTo < endOfDay)
+            .Join(
+                dbContext.Tenants,
+                subscription => subscription.TenantId,
+                tenant => tenant.Id,
+                (subscription, tenant) => new { Subscription = subscription, Tenant = tenant })
+            .Join(
+                dbContext.TenantPackages,
+                combined => combined.Subscription.TenantPackageId,
+                package => package.Id,
+                (combined, package) => new RenewalReminderCandidate
+                {
+                    Subscription = combined.Subscription,
+                    Tenant = combined.Tenant,
+                    Package = package
+                });
+
+        // 2. 返回候选列表
+        return await query.ToListAsync(cancellationToken);
+    }
+
+    /// <inheritdoc />
+    public async Task<IReadOnlyList<TenantSubscription>> FindExpiredActiveSubscriptionsAsync(
+        DateTime now,
+        CancellationToken cancellationToken = default)
+    {
+        // 1. 查询已到期仍为 Active 的订阅
+        return await dbContext.TenantSubscriptions
+            .Where(s => s.Status == SubscriptionStatus.Active && s.EffectiveTo < now)
+            .ToListAsync(cancellationToken);
+    }
+
+    /// <inheritdoc />
+    public async Task<IReadOnlyList<TenantSubscription>> FindGracePeriodExpiredSubscriptionsAsync(
+        DateTime now,
+        int gracePeriodDays,
+        CancellationToken cancellationToken = default)
+    {
+        // 1. 查询宽限期已结束的订阅
+        return await dbContext.TenantSubscriptions
+            .Where(s => s.Status == SubscriptionStatus.GracePeriod
+                        && s.EffectiveTo.AddDays(gracePeriodDays) < now)
+            .ToListAsync(cancellationToken);
+    }
+
     #endregion
 
     #region 套餐查询

src/Infrastructure/TakeoutSaaS.Infrastructure/App/Repositories/EfTenantBillingRepository.cs

@@ -120,6 +120,20 @@ public sealed class EfTenantBillingRepository(TakeoutAppDbContext context) : ITe
             .FirstOrDefaultAsync(x => x.TenantId == tenantId && x.StatementNo == statementNo, cancellationToken);
     }
 
+    /// <inheritdoc />
+    public Task<bool> ExistsNotCancelledByPeriodStartAsync(
+        long tenantId,
+        DateTime periodStart,
+        CancellationToken cancellationToken = default)
+    {
+        return context.TenantBillingStatements.AsNoTracking()
+            .AnyAsync(
+                x => x.TenantId == tenantId
+                     && x.PeriodStart == periodStart
+                     && x.Status != TenantBillingStatus.Cancelled,
+                cancellationToken);
+    }
+
     /// <inheritdoc />
     public Task AddAsync(TenantBillingStatement bill, CancellationToken cancellationToken = default)
     {

src/Infrastructure/TakeoutSaaS.Infrastructure/App/Repositories/EfTenantNotificationRepository.cs

@@ -56,6 +56,23 @@ public sealed class EfTenantNotificationRepository(TakeoutAppDbContext context)
             .FirstOrDefaultAsync(x => x.TenantId == tenantId && x.Id == notificationId, cancellationToken);
     }
 
+    /// <inheritdoc />
+    public Task<bool> ExistsByMetadataAsync(
+        long tenantId,
+        string title,
+        string metadataJson,
+        DateTime sentAfter,
+        CancellationToken cancellationToken = default)
+    {
+        return context.TenantNotifications.AsNoTracking()
+            .AnyAsync(
+                x => x.TenantId == tenantId
+                     && x.Title == title
+                     && x.MetadataJson == metadataJson
+                     && x.SentAt >= sentAfter,
+                cancellationToken);
+    }
+
     /// <inheritdoc />
     public Task AddAsync(TenantNotification notification, CancellationToken cancellationToken = default)
     {