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- Removed assets/final/ (legacy, superseded by workspaces)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, 4 deletions

diff --git a/assets/final/shaders/test_snippet_a.wgsl b/assets/final/shaders/test_snippet_a.wgsl
deleted file mode 100644
index 732973d..0000000
--- a/assets/final/shaders/test_snippet_a.wgsl
+++ /dev/null
@@ -1,4 +0,0 @@
-// test_snippet_a.wgsl
-fn snippet_a() -> f32 {
-    return 1.0;
-}