feat(core): recognize unsuffixed WebGL x3 vertex formats

[ibgreen]

Summary

• propose unsuffixed aliases such as unorm8x3 and uint16x3 for the existing -webgl x3 vertex formats
• make 8-bit x3 format inference return the canonical uint8x3-webgl and sint8x3-webgl names
• classify unsuffixed aliases as WebGL-only so device.isVertexFormatSupported() reports them as unsupported on WebGPU and WebGPU pipeline creation rejects them before they reach the native API

Motivation

deck.gl derives some attribute format strings from a component type and size. Accepting the resulting unsuffixed x3 names would let it use luma.gl's format decoder and device capability API instead of duplicating WebGPU format rules.

These aliases were not previously declared public constants, so this is intentionally separated from the backwards-compatibility fixes in #2758. It is an independent API proposal: callers can alternatively be required to emit the existing canonical -webgl names.

Validation

• yarn lint fix
• yarn build
• focused headless tests: 8 passed
• yarn test: all 178 node tests pass; the local headless run has the same three unrelated WebGPU failures reproduced on clean master (DGGS A5 decoding and the storage-backed arrow polygon test)