New image built from upstream base-atomic (no desktop), adding only gnome-shell
+ gdm + gnome-remote-desktop + pipewire/portal + foot + Flatpak + Kanidm.
recommends=false to stay lean. Configures GNOME Remote Desktop headless remote
login on first boot (TLS + credentials + enable). Firefox preinstalled as a
per-user Flatpak. Add it to the CI matrix and prune both images.
