Primary hue maps through ColorMath.HueOutsideBand; the secondary takes the
out-of-band side; fog tint and light derive from primary. Band edges are
SunHueExcludedStart/End (75 and 165 degrees by default).
Not yet verified on Yggdrasil at this commit.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>