Scene reads skyBox._cubeMap as the environment map that lights models, in
the TEME, flipY layout of Cesium's own sky box; the ICRF Milky Way would
light them rotated. Rename the field so models keep Cesium's default.
Test the anime fade on a real StarrySky and that the viewer gets the sky
as an option (skyBox: false would drop the Sun and Moon). Correct three
comments on the star limit and the Milky Way levels.
Co-Authored-By: Claude Opus 5.5 <[email protected]>