Apply a validated split/rehost plan atomically. Every opening, filling and
void relation keeps its identity; only the selected occurrence receives
fresh placements and its void relation's host changes. Source placement
records stay untouched. The caller decides the final host/fit for all cuts;
this batch never validates against intermediate single-move positions.
Apply a validated split/rehost plan atomically. Every opening, filling and void relation keeps its identity; only the selected occurrence receives fresh placements and its void relation's host changes. Source placement records stay untouched. The caller decides the final host/fit for all cuts; this batch never validates against intermediate single-move positions.