feat(extensions): support ClipExtension on WebGPU

[ibgreen-openai]

Goal

Enable the clipping path that MVTLayer needs to render on WebGPU.

This is a stacked follow-up to #10564, which contains the general binary-geometry and WebGPU vertex-buffer fixes. Its base should be changed to master after that prerequisite merges.

Changes

• add WGSL clip shader hooks to deck.gl's shader assembler
• merge luma.gl shader plugins through mergeShaders
• use luma.gl's uniform-only clipShaderPlugin for ClipExtension on WebGPU
• keep the existing shader-module/injection implementation unchanged on WebGL
• wire clip hooks into ScatterplotLayer, PathLayer, and SolidPolygonLayer, covering MVTLayer's circle, line, stroke, and fill sublayers
• enable MVTLayer render tests on WebGPU and document the initial support scope

Validation

• yarn lint
• npx vitest run --project headless test/modules/core/utils/shader.spec.ts test/modules/extensions/clip.spec.ts — 3 tests passed
• RENDER_TEST_DEVICE=webgpu npx vitest run --project render test/render/test-cases/mvt-layer.spec.ts — 6 passed, 1 backend group skipped
• RENDER_TEST_DEVICE=webgl npx vitest run --project render test/render/test-cases/mvt-layer.spec.ts — 6 passed, 1 backend group skipped
• commit hook node suites — 15 tests passed
• yarn build completed both the WebGL-only and WebGPU TypeScript/declaration/package builds; its final lerna run build phase was blocked by an unrelated Nx duplicate-project-name collision among external Codex worktrees

[coveralls]

Coverage is 82.4% — codex/webgpu-mvt-clipping into codex/webgpu-mvt-prerequisites. No base build found for codex/webgpu-mvt-prerequisites.

[Pessimistress]

Why not use the same hook names as WebGL: FILTER_POSITION / FILTER_COLOR? Does it make sense to insert hooks into every layer only for a specific extension?