jan/feature/20260818-lib-app-add-root-cmd into master Expose __root_cmd (the command which may or may not be mounted at the root of the subcommand hierarchy) as _root_cmd() to derived classes. This supports jw-ev's App base class, which specializes it to get hold of jw.ev.app.Cmd's specific properties. Signed-off-by: Jan Lindemann <jan@janware.com>