Lumavane Shaders

Design, GLSL implementation, documentation:
- Original work created for the Lumavane Shaders project.
- `shaders/tex/lumavane_noise.png` is an original generated noise texture used
  for subtle post-process dithering.

Compatibility references:
- Iris shaderpack documentation
- OptiFine-style shaderpack format documentation

No code, assets, comments, names, or visual identity were copied from SEUS,
Bliss, BSL, Sildur, or any other shaderpack.
