Haste v21 - Underwater Rays Tuning (development build)

Purpose
- Correct the broad, high-contrast blue ribbons visible in v20 screenshots.
- Use narrower, softer world-locked beam ribbons and a tighter screen-space cone.
- Make the world-locked fallback lower intensity than screen-space visibility.
- Soften channel-dependent absorption and reduce underwater fog density so distant terrain stays legible while unlit water remains dark.
- Slightly protect emissive sources from deep-water fog.

Performance
- Does not add rendering passes or texture samplers.
- Keeps the existing per-profile underwater ray sample count.
- Uses the same fixed math functions with slightly tighter masks.

Validation
- ZIP integrity and source-level structural checks performed.
- Not compiled or runtime-tested in Minecraft/Iris; validate in-game before release.
