feat(scheduler): 引入调度快照缓存与 outbox 回放

- 调度热路径优先读 Redis 快照，保留分组排序语义
- outbox 回放 + 全量重建纠偏，失败重试不推进水位
- 自动 Atlas 基线对齐并同步调度配置示例

backend/internal/service/wire.go

@@ -86,6 +86,19 @@ func ProvideConcurrencyService(cache ConcurrencyCache, accountRepo AccountReposi
 	return svc
 }
 
+// ProvideSchedulerSnapshotService creates and starts SchedulerSnapshotService.
+func ProvideSchedulerSnapshotService(
+	cache SchedulerCache,
+	outboxRepo SchedulerOutboxRepository,
+	accountRepo AccountRepository,
+	groupRepo GroupRepository,
+	cfg *config.Config,
+) *SchedulerSnapshotService {
+	svc := NewSchedulerSnapshotService(cache, outboxRepo, accountRepo, groupRepo, cfg)
+	svc.Start()
+	return svc
+}
+
 // ProvideOpsMetricsCollector creates and starts OpsMetricsCollector.
 func ProvideOpsMetricsCollector(
 	opsRepo OpsRepository,
@@ -201,6 +214,7 @@ var ProviderSet = wire.NewSet(
 	NewTurnstileService,
 	NewSubscriptionService,
 	ProvideConcurrencyService,
+	ProvideSchedulerSnapshotService,
 	NewIdentityService,
 	NewCRSSyncService,
 	ProvideUpdateService,