January's decals copy of the bsp3d_get_plane_from_designator inline branches on the sign bit (jns), matching the punpckhdq upstream spelling. Full build: decals::_bsp3d_get_plane_from_designator exact (112 padded), 0 regressions across all bsp3d.h consumers, parks clean.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>