TRELLIS meshes never bone-heat directly (non-manifold even after weld); the watertight
proxy solves, POLYINTERP_NEAREST transfers (ACTIVE->SELECTED — reversed is a silent
no-op), 4x smooth knocks down shell-bleed spikes. Proven on the tradie: 194k->14k tris,
22 real groups, clean walk at game scale. --tris 0 = old direct path for authored meshes.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>