feat(sync): attach metrics recorder to sync engine if database is available

Added functionality to attach a metrics recorder to the sync engine,
allowing for performance tracking when the database is accessible.
If the database is not found or cannot be opened, logging is performed
and sync continues without metrics.

Author: mrz1836

internal/cli/sync.go

@@ -273,6 +273,10 @@ func runSync(cmd *cobra.Command, args []string) error {
 		return fmt.Errorf("failed to initialize sync engine: %w", err)
 	}
 
+	// Attach sync metrics recorder if database is available
+	closeMetrics := tryAttachMetricsRecorder(engine, logrus.StandardLogger())
+	defer closeMetrics()
+
 	// Execute sync
 	if err := engine.Sync(ctx, targets); err != nil {
 		return fmt.Errorf("sync failed: %w", err)
@@ -319,6 +323,10 @@ func createRunSync(flags *Flags) func(*cobra.Command, []string) error {
 			return fmt.Errorf("failed to initialize sync engine: %w", err)
 		}
 
+		// Attach sync metrics recorder if database is available
+		closeMetrics := tryAttachMetricsRecorder(engine, logger)
+		defer closeMetrics()
+
 		// Execute sync
 		if err := engine.Sync(ctx, targets); err != nil {
 			return fmt.Errorf("sync failed: %w", err)
@@ -440,6 +448,33 @@ func loadConfigWithFlags(flags *Flags, logger *logrus.Logger) (*config.Config, e
 	return cfg, nil
 }
 
+// tryAttachMetricsRecorder attempts to open the database and attach a sync metrics
+// recorder to the engine. If the database does not exist or cannot be opened, it
+// logs and returns a no-op closer so sync continues without metrics.
+// The returned function must be called (typically via defer) when the sync completes.
+func tryAttachMetricsRecorder(engine *sync.Engine, log *logrus.Logger) func() {
+	path := getDBPath()
+	if _, err := os.Stat(path); os.IsNotExist(err) {
+		log.Debug("Database not found; sync metrics will not be recorded")
+		return func() {}
+	}
+
+	database, err := db.Open(db.OpenOptions{
+		Path:     path,
+		LogLevel: logger.Silent,
+	})
+	if err != nil {
+		log.WithError(err).Warn("Failed to open database; sync metrics will not be recorded")
+		return func() {}
+	}
+
+	repo := db.NewBroadcastSyncRepo(database.DB())
+	adapter := sync.NewDBMetricsAdapter(repo)
+	engine.SetSyncMetricsRecorder(adapter)
+
+	return func() { _ = database.Close() }
+}
+
 // createSyncEngine initializes the sync engine with all required dependencies
 func createSyncEngine(ctx context.Context, cfg *config.Config) (*sync.Engine, error) {
 	logger := logrus.StandardLogger()