refactor(scheduler): migrate outbox and model registry to scheduler-based execution

Replace internal goroutine-based timing loops with scheduler integration
for SyncOutboxService and ModelRegistryService. Both services now expose
RunOnce() methods called by the central scheduler instead of managing
their own background loops.

- Add Interval() and RunOnce() methods to SyncOutboxService
- Add RefreshEvery() and RunOnce() methods to ModelRegistryService
- Remove started flag from SyncOutboxService struct
- Move scheduler.Start() after all services are initialized
- Ensure initial model registry refresh before scheduler starts

cmd/server/main.go

@@ -164,6 +164,7 @@ func main() {
 
 	// 4. Setup Services and Handlers
 	syncService := service.NewSyncService(rdb)
+	var outboxService *service.SyncOutboxService
 	if cfg.SyncOutbox.Enabled {
 		outboxCfg := service.SyncOutboxConfig{
 			Enabled:    cfg.SyncOutbox.Enabled,
@@ -171,11 +172,8 @@ func main() {
 			BatchSize:  cfg.SyncOutbox.BatchSize,
 			MaxRetries: cfg.SyncOutbox.MaxRetries,
 		}
-		outboxService := service.NewSyncOutboxService(db, syncService, outboxCfg, logger)
+		outboxService = service.NewSyncOutboxService(db, syncService, outboxCfg, logger)
 		syncService.SetOutbox(outboxService)
-		outboxCtx, cancelOutbox := context.WithCancel(context.Background())
-		defer cancelOutbox()
-		go outboxService.Start(outboxCtx)
 	}
 	logPartitioner := service.NewLogPartitioner(logDB, cfg.Log.Partitioning)
 	if logPartitioner.Enabled() {
@@ -202,13 +200,15 @@ func main() {
 	alertDetectorConfig := cron.DefaultAlertDetectorConfig()
 	alertDetector := cron.NewAlertDetector(db, logDB, rdb, service.NewStatsService(rdb), alertDetectorConfig, logger)
 
-	// Setup scheduler
+	// Setup scheduler (jobs are added incrementally, Start() called after all services initialized)
 	sched := scheduler.New(scheduler.WithLogger(logger), scheduler.WithSkipIfRunning())
 	sched.Every("quota-reset", time.Duration(cfg.Quota.ResetIntervalSeconds)*time.Second, quotaResetter.RunOnce)
 	sched.Every("log-cleanup", time.Hour, logCleaner.RunOnce)
 	sched.Every("token-refresh", time.Duration(cfg.TokenRefresh.IntervalSeconds)*time.Second, tokenRefresher.RunOnce)
 	sched.Every("alert-detection", time.Minute, alertDetector.RunOnce)
-	sched.Start()
+	if outboxService != nil && outboxService.Enabled() {
+		sched.Every("sync-outbox", outboxService.Interval(), outboxService.RunOnce)
+	}
 	defer sched.Stop()
 
 	adminService, err := service.NewAdminService()
@@ -243,7 +243,12 @@ func main() {
 	if err := syncService.SyncAll(db); err != nil {
 		logger.Warn("initial sync warning", "err", err)
 	}
-	modelRegistryService.Start(context.Background())
+	// Initial model registry refresh before scheduler starts
+	if modelRegistryService.Enabled() {
+		modelRegistryService.RunOnce(context.Background())
+		sched.Every("model-registry-refresh", modelRegistryService.RefreshEvery(), modelRegistryService.RunOnce)
+	}
+	sched.Start()
 
 	// 5. Setup Gin Router
 	r := gin.Default()