Bitwise. MakeOwnSlot copies the model as it was before the topology and reads only what the placement does not
change (cell, reflections, the engine's kind, the B ceiling), so the slots are now built on their threads right
after the start score, beside the rigid-body and group-B placement, and joined where they were built before
(also where the placement throws). The "slots" stage goes from 0.23 s to 0 on 9yl4; the placement is not
slowed (0.59 -> 0.60 s). Refined CIF md5 unchanged on 5reo, 5f6m, 9yl4, 7d98, 5f6m MD start (GPU) and 6o2h
(CPU); side by side = one at a time. Wall: 5reo 1.46-1.53 -> 1.54, 5f6m 2.26 -> 2.21, 9yl4 7.03 -> 6.83, 7d98
3.65 -> 3.56, 5f6m MD start 4.20 -> 4.15 s.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015CeEGgpKdfkCTJb3YNMJcu
(cherry picked from commit 0752a921a4293d4213894e3242c4ef36d8ce2a05)