setPreferredServers method
Set preferred S&F servers (MX-like)
Implementation
Future<void> setPreferredServers(List<SFServerPreference> servers) async {
_logger.info('Setting ${servers.length} preferred servers');
// This would update the config, but since config is final, we'd need to
// recreate the client or have a mutable preferences list
// For now, log a warning
_logger.warning('setPreferredServers: Consider recreating client with new config');
}