- packagechooser_dm.conf (runtime + online ref): switch from netinstall-select
to netinstall-add, move SDDM/LightDM/LXDM/greetd/LY packages inline into the
chooser items; both copies byte-identical in content
- netinstall.yaml (runtime + online ref): drop the now-inline DM groups; bring
the online ref's Default group in line with runtime (add falkon,
networkmanager, pipewire, wireplumber)