Replaces RockMeshing/AssignRockMeshes and the renderer's slot bucketing (findings scale-lookup-unpinned,
renderer-index-wiring-unpinned). The build gate message names the mesh and the field, not the radii.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
DrawAhead.AssignRockMeshes ranks rocks by unworn size onto meshes in ascending radius; RockScale divides the
gameplay radius by the mesh's measured radius; ChunkAt is the one rock position for the renderer and the reticle
(ChunkHeight folded into it). InstancedMesh.Radius is filled and verified by RockMeshRadius. Tests pin the
assignment, the scale and that the renderer and reticle call DrawAhead (finding owner-not-pinned).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>