Refactor: Reorganize workspaces and remove assets/ directory

Workspace structure now:
- workspaces/{main,test}/obj/      (3D models)
- workspaces/{main,test}/shaders/  (WGSL shaders)
- workspaces/{main,test}/music/    (audio samples)

Changes:
- Moved workspaces/*/assets/music/ → workspaces/*/music/
- Updated assets.txt paths (assets/music/ → music/)
- Moved test_demo.{seq,track} to tools/
- Moved assets/originals/ → tools/originals/
- Removed assets/common/ (legacy, duplicated in workspaces)
- Removed assets/final/ (legacy, superseded by workspaces)
- Updated hot-reload paths in main.cc
- Updated CMake references for test_demo and validation
- Updated gen_spectrograms.sh paths

handoff(Claude): Workspace reorganization complete

1 files changed, 0 insertions, 6 deletions

diff --git a/assets/common/shaders/render/lighting_utils.wgsl b/assets/common/shaders/render/lighting_utils.wgsl
deleted file mode 100644
index d2fd2e2..0000000
--- a/assets/common/shaders/render/lighting_utils.wgsl
+++ /dev/null
@@ -1,6 +0,0 @@
-fn calculate_lighting(color: vec3<f32>, normal: vec3<f32>, pos: vec3<f32>, shadow: f32) -> vec3<f32> {
-    let light_dir = normalize(vec3<f32>(1.0, 1.0, 1.0));
-    let diffuse = max(dot(normal, light_dir), 0.0);
-    let lighting = diffuse * (0.1 + 0.9 * shadow) + 0.1; // Ambient + Shadowed Diffuse
-    return color * lighting;
-}