addFileTransferCommands method
Adds :download, :upload and :drive to this registry.
driveHome overrides the home base :drive keeps its mount store under
(<driveHome>/.omnyshell/mounts.json; default: the user's home, see
DriveManager.open); tests point it at a temporary directory.
Implementation
void addFileTransferCommands({String? driveHome}) {
register(_DownloadCommand());
register(_UploadCommand());
register(_DriveCommand(home: driveHome));
}