feat(cnn_v3): GBufDeferredEffect — simple deferred render (albedo * shadow)

New effect unpacks feat_tex0/feat_tex1 and outputs albedo * shadow.
Replaces CNNv3Effect in cnn_v3_test sequence until training is complete.
37/37 tests passing.

handoff(Gemini): GBufDeferredEffect wired in timeline; CNN v3 pipeline: GBufferEffect → GBufDeferredEffect → sink.

1 files changed, 23 insertions, 0 deletions

diff --git a/cnn_v3/src/gbuf_deferred_effect.h b/cnn_v3/src/gbuf_deferred_effect.h
new file mode 100644
index 0000000..4daf13d
--- /dev/null
+++ b/cnn_v3/src/gbuf_deferred_effect.h
@@ -0,0 +1,23 @@
+// GBufDeferredEffect — simple deferred render from packed G-buffer.
+// Inputs: feat_tex0, feat_tex1 (rgba32uint). Output: albedo * shadow (rgba8unorm).
+
+#pragma once
+#include "gpu/effect.h"
+#include "gpu/uniform_helper.h"
+#include "gpu/wgpu_resource.h"
+
+class GBufDeferredEffect : public Effect {
+ public:
+  GBufDeferredEffect(const GpuContext& ctx,
+                     const std::vector<std::string>& inputs,
+                     const std::vector<std::string>& outputs,
+                     float start_time, float end_time);
+
+  void render(WGPUCommandEncoder encoder,
+              const UniformsSequenceParams& params,
+              NodeRegistry& nodes) override;
+
+ private:
+  RenderPipeline pipeline_;
+  BindGroup bind_group_;
+};