feat(shaders): Add Möller-Trumbore ray-triangle intersection

Implements ray-triangle intersection algorithm for future mesh raytracing support.

Changes:
- Add ray_triangle.wgsl with TriangleHit struct and intersection function
- Register shader snippet in asset system (SHADER_RAY_TRIANGLE)
- Add shader composer registration for #include "ray_triangle" support

Returns:
- hit.uv: Barycentric coordinates (for texture mapping)
- hit.z: Parametric distance along ray
- hit.N: Triangle face normal
- hit.hit: Boolean indicating intersection

Task: Progress on SDF for mesh (related to Task #18)
Algorithm: Fast, Minimum Storage Ray-Triangle Intersection (Möller-Trumbore)
Size: ~30 lines WGSL, negligible binary impact

1 files changed, 1 insertions, 0 deletions

diff --git a/assets/final/demo_assets.txt b/assets/final/demo_assets.txt
index 256f246..5d40f7f 100644
--- a/assets/final/demo_assets.txt
+++ b/assets/final/demo_assets.txt
@@ -27,6 +27,7 @@ SHADER_COMMON_UNIFORMS, NONE, shaders/common_uniforms.wgsl, "Common Uniforms Sni
 SHADER_SDF_PRIMITIVES, NONE, shaders/sdf_primitives.wgsl, "SDF Primitives Snippet"
 SHADER_LIGHTING, NONE, shaders/lighting.wgsl, "Lighting Snippet"
 SHADER_RAY_BOX, NONE, shaders/ray_box.wgsl, "Ray-Box Intersection Snippet"
+SHADER_RAY_TRIANGLE, NONE, shaders/ray_triangle.wgsl, "Ray-Triangle Intersection Snippet (Möller-Trumbore)"
 SHADER_MAIN, NONE, shaders/main_shader.wgsl, "Main Heptagon Shader"
 SHADER_PARTICLE_COMPUTE, NONE, shaders/particle_compute.wgsl, "Particle Compute Shader"
 SHADER_PARTICLE_RENDER, NONE, shaders/particle_render.wgsl, "Particle Render Shader"