Climate (Core) layers a continuous seasonal-plus-daily temperature and the
current season over the Calendar, registered via context.UseClimate. A new
Lighting module (Graphics) adds DayNight: a daylight factor and ambient
color from the calendar's time of day, pushed into the renderer's new
AmbientLight (multiplied into world-space sprites only, so the scene
darkens at night while screen-space overlays stay readable) and exposed as
a sampleable SampleAt for the simulation. Both deterministic and GPU-free,
covered by tests; docs updated.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
