Replace unreliable raycast parity on open-shell meshes with editor-baked
voxel grids. ConcealmentVolume bakes an inside-mask per object using the
union of a generalized-winding-number test (solid material, robust to open
shells) and an exterior flood-fill (enclosed cavities). ConcealmentMeter
now prefers baked volumes via an O(1) world-space lookup through a registry,
falling back to the old concave parity only for un-baked colliders.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
