test_demo: Add beat-synchronized CNN post-processing with version selection

- Add --cnn-version <1|2> flag to select between CNN v1 and v2
- Implement beat_phase modulation for dynamic blend in both CNN effects
- Fix CNN v2 per-layer uniform buffer sharing (each layer needs own buffer)
- Fix CNN v2 y-axis orientation to match render pass convention
- Add Scene1Effect as base visual layer to test_demo timeline
- Reorganize CNN v2 shaders into cnn_v2/ subdirectory
- Update asset paths and documentation for new shader organization

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

2 files changed, 2 insertions, 2 deletions

diff --git a/training/export_cnn_v2_shader.py b/training/export_cnn_v2_shader.py
index 3c53ce2..add28d2 100755
--- a/training/export_cnn_v2_shader.py
+++ b/training/export_cnn_v2_shader.py
@@ -144,7 +144,7 @@ fn main(@builtin(global_invocation_id) id: vec3<u32>) {{
 }}
 """
 
-    output_path = Path(output_dir) / f"cnn_v2_layer_{layer_idx}.wgsl"
+    output_path = Path(output_dir) / "cnn_v2" / f"cnn_v2_layer_{layer_idx}.wgsl"
     output_path.write_text(shader_code)
     print(f"  → {output_path}")
 
diff --git a/training/export_cnn_v2_weights.py b/training/export_cnn_v2_weights.py
index 723f572..d8c7c10 100755
--- a/training/export_cnn_v2_weights.py
+++ b/training/export_cnn_v2_weights.py
@@ -248,7 +248,7 @@ fn main(@builtin(global_invocation_id) id: vec3<u32>) {
 }
 """
 
-    output_path = Path(output_dir) / "cnn_v2_compute.wgsl"
+    output_path = Path(output_dir) / "cnn_v2" / "cnn_v2_compute.wgsl"
     output_path.write_text(shader_code)
     print(f"  → {output_path}")