Add support for WGSL uniform_buffer_standard_layout extension

[mvaligursky]

Feature

Add support for the WGSL uniform_buffer_standard_layout language extension, shipped in Chrome 144.

This extension lets uniform buffers use the storage-buffer memory layout, removing the strict 16-byte alignment requirements normally imposed on uniform buffer members. The engine probes a number of wgslLanguageFeatures (e.g. unrestricted_pointer_parameters, pointer_composite_access, texture_and_sampler_let) but does not currently detect or make use of uniform_buffer_standard_layout.

Benefit

• Tighter, simpler uniform buffer packing — avoids padding members up to 16-byte boundaries.
• Can reduce uniform buffer size and simplify CPU-side layout/packing logic.

Notes

• Requires detecting navigator.gpu.wgslLanguageFeatures.has('uniform_buffer_standard_layout'), exposing a capability flag, and optionally relaxing uniform buffer layout/packing when available.
• Ref: https://developer.chrome.com/blog/new-in-webgpu-144