Review W4: the bend height was normalised per submesh, so a trunk + canopy
detail doodad tore apart at the seam; the span is now taken over all of the
model's submeshes. Review W5: clutter meshes carry UV_1 (VERTEX_UVS_B), so the
six clutter pipelines are also warmed on the POS+NORMAL+UV0+UV1+COLOR quad.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
