Native Night Support

If night support was build in, aka, you lower the sun altitule, and then it is automatically into the night. So that would include sky brightness, sun intensity, the moon. It would not just set the sky brightness to 0.1, it would change the engine for the sky. Lighting would change to the moon, the fog would auto-enable, the Fullbright horizon effect would go away.

The issue does not name any files, tests, or entry points. Start by locating the renderer code for sun altitude, sky brightness, moon lighting, fog, and the Fullbright horizon effect, then determine how these systems currently interact. Done would require coordinated automatic night behavior across those effects, with tests or rendered examples confirming the result.

Written by the indexing model from the issue text.