Add nomarchy.nightlight (opt-in): a scheduled colour-temperature shift via
the HM services.hyprsunset module -- warm (.temperature, default 4000K) at
night, identity (no shift) by day, switching at .sunset / .sunrise. Two
time-based hyprsunset profiles, so hyprsunset handles the schedule and the
on-login state. New modules/home/nightlight.nix, imported in the home module.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>