fix(layers): support binary geometry on WebGPU

[ibgreen-openai]

Goal

Prepare ScatterplotLayer and PathLayer to render binary geometry reliably on WebGPU. These fixes are prerequisites for enabling binary MVTLayer rendering, but do not add clipping support themselves.

Changes

• Pack ScatterplotLayer's scalar/color instance attributes into one WebGPU buffer group so binary points remain within WebGPU's vertex-buffer limit.
• Rename PathLayer's packed WebGPU parent attribute so it is not mistaken for an anchor-position attribute.
• Build PathLayer's WebGPU neighbor window directly from external binary getPath data, respecting XY/XYZ size, byte stride, and byte offset.
• Add a focused WebGPU binary GeoJSON regression test covering point and path pipeline validation and non-empty packed path positions.

Validation

• npx vitest run --project headless test/modules/layers/geojson-layer-webgpu.spec.ts — passed
• commit hook node tests — 15 passed
• yarn lint — passed
• git diff --check — passed
• yarn build — WebGL-only and WebGPU TypeScript/declaration/package compilation passed; the final unrelated lerna run build wrapper failed to construct its Nx project graph in the isolated worktree

[coveralls]

coverage: 82.418% (-0.08%) from 82.497% — codex/webgpu-mvt-prerequisites into master

[Pessimistress]

Binary attribute is handled in the Tesselator.