- packagechooser_dm.conf (offline + online copies): LightDM group now
installs lightdm-slick-greeter + antergos-lightdm-config and shows a
screenshot. The live-overlay was overriding the branding package's
config with a bare LightDM group (no greeter), so displaymanager's
greeter_setup() aborted Xfce+LightDM online installs.
- profile.yaml: add zenity to rootfs packages. antergos-offline-install
uses zenity exclusively but only yad was installed, so the offline
installer silently did nothing on double-click.