Fix XR camera layers inheritance

[wrangelvid]

The previous code used narrow bitmasks that only preserved layers 0-2.
We changed the bitmask operations to preserve all inhertied layers while still correctly assigning eye-specific layers.

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	355.34 84.47	355.34 84.47	+2 B +1 B
WebGPU	618.89 171.93	618.9 171.93	+2 B +1 B
WebGPU Nodes	617.5 171.68	617.5 171.68	+2 B +1 B

🌳 Bundle size after tree-shaking

Minimal build including a renderer, camera, empty scene, and dependencies.

	Before	After	Diff
WebGL	487.5 119.33	487.5 119.33	+2 B +1 B
WebGPU	691.15 187.57	691.16 187.57	+2 B +1 B
WebGPU Nodes	641 174.81	641 174.81	+2 B +1 B