refactor: complete removal of 'Effect' suffix from C++ class names

Update effect class definitions in headers and implementations to match
timeline.seq naming convention. All tests passing (34/34).

Classes renamed:
- PassthroughEffect → Passthrough
- GaussianBlurEffect → GaussianBlur
- PlaceholderEffect → Placeholder
- HeptagonEffect → Heptagon
- ParticlesEffect → Particles
- RotatingCubeEffect → RotatingCube
- Hybrid3DEffect → Hybrid3D
- FlashEffect → Flash
- PeakMeterEffect → PeakMeter

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

1 files changed, 3 insertions, 3 deletions

diff --git a/src/effects/flash_effect.h b/src/effects/flash_effect.h
index b9bbff8..9e7a326 100644
--- a/src/effects/flash_effect.h
+++ b/src/effects/flash_effect.h
@@ -5,12 +5,12 @@
 #include "gpu/effect.h"
 #include "gpu/uniform_helper.h"
 
-class FlashEffect : public Effect {
+class Flash : public Effect {
  public:
-  FlashEffect(const GpuContext& ctx,
+  Flash(const GpuContext& ctx,
               const std::vector<std::string>& inputs,
               const std::vector<std::string>& outputs);
-  ~FlashEffect() override;
+  ~Flash() override;
 
   void render(WGPUCommandEncoder encoder,
               const UniformsSequenceParams& params,