OpenXR's grip +X is normal to the palm but points away from it on the left hand
and into it on the right, which is exactly what makes both grips carry the same
orientation when the hands hold a wheel symmetrically. The fingers therefore run
along -Y on both hands, and it is the geometry across the palm that mirrors.
Building the right hand's fingers on +Y instead left them pointing at the player
while the real hand faced forward.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>