[zigai]

CommandError subclassed InterfacyError, so except InterfacyError in an application also caught the application's own command failures. CommandError now subclasses Exception, and run() prints its message through a separate path instead of special-casing it inside the generic exception logger.

With full_error_traceback=True, a CommandError now prints only its message, without traceback frames. Other exceptions keep the traceback.

Verification

• A command that raises CommandError("Settings file is stale; run setup again.") from a ValueError prints only that message and exits 1
• A command that raises RuntimeError("secret detail") prints only RuntimeError and exits 1
• An executable flag --diagnose that raises CommandError("Config is broken.") prints that message and exits 1
• issubclass(CommandError, InterfacyError) is False in the installed package