refactor: Bundle GPU context into GpuContext struct

- Created GpuContext struct {device, queue, format}
- Updated Effect/PostProcessEffect to take const GpuContext&
- Updated all 19 effect implementations
- Updated MainSequence.init() and LoadTimeline() signatures
- Updated generated timeline files
- Updated all test files
- Added gpu_get_context() accessor and fixture.ctx() helper

Fixes test_mesh.cc compilation error from g_device/g_queue/g_format conflicts.
All targets build successfully.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/gpu/effects/hybrid_3d_effect.h b/src/gpu/effects/hybrid_3d_effect.h
index 8e2fef9..3a4e87c 100644
--- a/src/gpu/effects/hybrid_3d_effect.h
+++ b/src/gpu/effects/hybrid_3d_effect.h
@@ -12,7 +12,7 @@
 
 class Hybrid3DEffect : public Effect {
  public:
-  Hybrid3DEffect(WGPUDevice device, WGPUQueue queue, WGPUTextureFormat format);
+  Hybrid3DEffect(const GpuContext& ctx);
   virtual ~Hybrid3DEffect() override = default;
 
   void init(MainSequence* demo) override;