Plan: WebGPU + glTF Renderer in Rust — moved

Moved to OxidANT, beside the crate it describes: decision D6 gave OxidANT the WebGPU renderer’s code and its docs. This is a pointer, not a copy.

• checkout: third_party/OxidANT/crates/webgpu_renderer/docs/webgpu-gltf-rust-plan.md

• web: Kataglyphis/OxidANT (HEAD, not a branch name: it follows OxidANT’s default branch, develop)

Renderer docs that stayed here: gpu-golden-testing.md, model-loading.md, shader-sharing.md, webgpu-srgb-audit.md.