The previous centralization into enable-services.sh accidentally changed
semantics for three services: docker.socket, iwd.service, and
power-profiles-daemon.service used to be enabled with bare
'sudo systemctl enable' (no --now); chrootable_systemctl_enable promoted
them to 'enable --now' outside chroot.
For iwd this is the riskiest: it's typically what's keeping the installer
online, so starting it mid-install is at best a no-op and at worst can
disrupt the active network connection. For docker.socket and
power-profiles-daemon the change is cosmetic (the socket is already
inactive, the daemon does no harm to start) but the original intent was
deferral to first boot.
New helper in install/helpers/chroot.sh:
chrootable_systemctl_enable_only <unit> # plain enable, no --now
enable-services.sh uses it for the three services that were previously
bare-enabled. The other five (bluetooth, cups, cups-browsed,
avahi-daemon, linux-modules-cleanup) keep the --now behavior they had
under chrootable_systemctl_enable.