HASTE v30 — UNDERWATER DISTANCE FOG

Built from the uploaded v29 Haze development ZIP.

Changes:
- Added an independent Underwater Distance Fog toggle.
- Added Underwater Fog Start (0–24 blocks) so nearby water stays clearer while distant terrain fades smoothly.
- Kept Water Murk as the density control, preserving the existing biome-tinted fog colour and light-source protection.
- The fog toggle also removes its extinction contribution from the underwater shaft march when disabled.
- Exposed the options in Water & Reflections and set consistent defaults in all six profiles.
- No extra texture reads, render passes, or per-pixel loops were added; the fog remains a simple exponential blend.

Validation: archive and source consistency checks only. This environment does not have glslangValidator or a live Iris/Minecraft runtime, so the shader has not been compiled or tested in-game here.
