M12.2: gpu compositor and gpu effects

New L3 crate effectcraft-gpu: a wgpu compute backend for the per-frame
compositing walk (layer transforms with the CPU's nearest/bilinear/bicubic
sampling and minification pre-filter, motion-blur accumulation, track
mattes, Preserve Transparency, layer style passes and knockout, all 38
blend modes as a WGSL port of color::blend, 8/16 bpc clamp+quantise,
colour-space conversions). 3D runs, adjustment and wireframe layers run on
the CPU between GPU steps. GPU effects with the CPU semantics: Gaussian,
Fast Box and Directional Blur, Glow, Levels, Curves, Hue/Saturation, Tint,
Fill, Gradient Ramp, Fractal Noise, Drop Shadow, Brightness & Contrast,
Exposure, Invert, Transform (registry gpu badge from effects::GPU_EFFECTS).

render: Backend (Cpu/Gpu/Auto) in RenderOpts, the Accelerator trait and
Renderer::accel, GPU effect chains in the effect stack, hooks for the GPU
walk. Project setting gpu_acceleration (Mercury GPU Acceleration / Software
Only), render.backend command, file.projectSettings renderer. Session and
Render Queue exports carry the accelerator. CLI --gpu and bench --gpu.

Tests compare GPU vs CPU renders (blend modes x bit depths, transforms,
masks, mattes, motion blur, colour management, styles, collapse,
adjustment fallback, every GPU effect) and skip without an adapter.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

Cargo.toml

@@ -23,6 +23,7 @@ effectcraft-text = { path = "crates/text" }
 effectcraft-effects = { path = "crates/effects" }
 effectcraft-track = { path = "crates/track" }
 effectcraft-render = { path = "crates/render" }
+effectcraft-gpu = { path = "crates/gpu" }
 effectcraft-media = { path = "crates/media" }
 effectcraft-export = { path = "crates/export" }
 effectcraft-expr = { path = "crates/expr" }
@@ -66,6 +67,11 @@ filmcraft-prores = { git = "https://github.com/storytold/filmcraft", rev = "89cf
 filmcraft-aac = { git = "https://github.com/storytold/filmcraft", rev = "89cfbf24f698b0f0e538eb7795929f19bbfb1dbb" }
 filmcraft-isobmff = { git = "https://github.com/storytold/filmcraft", rev = "89cfbf24f698b0f0e538eb7795929f19bbfb1dbb" }
 
+# gpu (the same wgpu eframe / egui-wgpu use)
+wgpu = { version = "30.0.1", features = ["fragile-send-sync-non-atomic-wasm"] }
+bytemuck = "1"
+pollster = "0.4"
+
 # ui
 egui = "0.36"
 eframe = { version = "0.36", default-features = false }
@@ -108,6 +114,9 @@ opt-level = 3
 [profile.dev.package.effectcraft-render]
 opt-level = 3
 
+[profile.dev.package.effectcraft-gpu]
+opt-level = 3
+
 [profile.dev.package.effectcraft-effects]
 opt-level = 3