DAYLIGHT / NIGHT GODRAY FIX

- DAYLIGHT_MULTIPLIER default is now 0.20 (20%) and remains independent from exposure.
- TWILIGHT_MULTIPLIER remains 0.85 (85%).
- Night godrays use a cool blue moonlight tint and the opposite celestial direction.
- Night godrays use the same thick mist profile as twilight.
- Night godrays keep shadow-map occlusion instead of fading to fully unshadowed light.
- Night atmospheric fog is tinted cool blue so it does not inherit orange sunset scattering.
- GODRAY_NIGHT_SHADOW_STRENGTH is exposed in the shader settings.
