Don't import classes on specific path in rectorphp/rector

Question

I have a rector setup for upgrading to laravel9 and php8.1, and it works good.

My question is, how to set up the config so that it imports the classes everywhere, but not in config/app.php?

return static function (RectorConfig $rectorConfig): void {
    $rectorConfig->parallel(seconds: 240, maxNumberOfProcess: 6);

    $rectorConfig->paths([
        __DIR__ . '/app',
        __DIR__ . '/bootstrap/app.php',
        __DIR__ . '/config',
        __DIR__ . '/database',
        __DIR__ . '/lang',
        __DIR__ . '/resources',
        __DIR__ . '/routes',
        __DIR__ . '/tests',
    ]);

    $rectorConfig->importNames();
    $rectorConfig->importShortClasses(false);

   ...

I'm avare of skip(), but that seems to work for files or rules, not config parameters...