fix: calculate beat_phase for FlashEffect and refactor uniforms

- seq_compiler.py: Calculate beat_phase from beat_time (was hardcoded 0.0f)
- Refactor: Replace CommonPostProcessUniforms with UniformsSequenceParams
- Remove duplicate struct definition in post_process_helper.h
- Update all CNN effects and tests to use unified uniform struct
- Fixes FlashEffect showing solid white instead of flashing to beat

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

2 files changed, 4 insertions, 4 deletions

diff --git a/cnn_v2/src/cnn_v2_effect.cc b/cnn_v2/src/cnn_v2_effect.cc
index 133087a..42aa2bb 100644
--- a/cnn_v2/src/cnn_v2_effect.cc
+++ b/cnn_v2/src/cnn_v2_effect.cc
@@ -377,7 +377,7 @@ void CNNv2Effect::update_bind_group(WGPUTextureView input_view) {
 }
 
 void CNNv2Effect::compute(WGPUCommandEncoder encoder,
-                          const CommonPostProcessUniforms& uniforms) {
+                          const UniformsSequenceParams& uniforms) {
   if (!initialized_ || !static_pipeline_ || !static_bind_group_)
     return;
 
@@ -446,7 +446,7 @@ void CNNv2Effect::compute(WGPUCommandEncoder encoder,
 }
 
 void CNNv2Effect::render(WGPURenderPassEncoder pass,
-                         const CommonPostProcessUniforms& uniforms) {
+                         const UniformsSequenceParams& uniforms) {
   (void)pass;
   (void)uniforms;
   // Compute-only effect, rendering is done by default composite pass
diff --git a/cnn_v2/src/cnn_v2_effect.h b/cnn_v2/src/cnn_v2_effect.h
index 7960b4f..b675736 100644
--- a/cnn_v2/src/cnn_v2_effect.h
+++ b/cnn_v2/src/cnn_v2_effect.h
@@ -19,9 +19,9 @@ class CNNv2Effect : public PostProcessEffect {
   void init(MainSequence* demo) override;
   void resize(int width, int height) override;
   void compute(WGPUCommandEncoder encoder,
-               const CommonPostProcessUniforms& uniforms) override;
+               const UniformsSequenceParams& uniforms) override;
   void render(WGPURenderPassEncoder pass,
-              const CommonPostProcessUniforms& uniforms) override;
+              const UniformsSequenceParams& uniforms) override;
   void update_bind_group(WGPUTextureView input_view) override;
 
   void set_beat_modulation(bool enabled, float scale = 1.0f) {