Add normalize input parsing

internal/normalize/normalize.go

@@ -14,6 +14,10 @@ func Run(ctx context.Context, cfg config.NormalizeConfig) error {
 		return err
 	}
 
+	if _, err := ParseFile(cfg.InputFile); err != nil {
+		return err
+	}
+
 	// TODO: Implement transcript normalization transformation.
 	return fmt.Errorf("normalize command is not implemented yet")
 }