scatter.js ray-marches a single-scattering Rayleigh+Mie atmosphere whose vertical optical depth is
sun.js's TAU, and bakes two tables into baked.scatter: transmittance to space by view elevation
(32x1) and sky radiance by azimuth from the sun x view elevation x sun elevation (7x32x12), RGB
half floats, little-endian base64, value x 64. Layout, exact decode and a GLSL sampler are in
src/sky/README.md. Tests pin layout, encoding, checksums and physical anchors (zenith transmittance
equals exp(-TAU); blue noon, red low sun toward the sun, black below the planet-shadow limit).
The per-sky sun {elevation_deg, azimuth_deg, color_linear}, ambient_linear and horizon_hex were
already baked in 7216456a; sun.js now exports TAU.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>