* 🐛 Keep multi-select variant switches refreshing every instance
Multi variants-switch ended each swap with select-shape, which replaced
the selection, interrupted layout/WASM work, and navigated once per copy
so only one instance looked updated under flex. Skip per-swap select and
layout in the batch, re-read live geometry, coalesce layout ids via a
companion DataEvent, then restore selection once. The same path covers
Assets component-multi-swap. Frontend tests lock select-shape count,
layout coalesce, and mixed no-op selections.
Closes#12829
AI-assisted-by: Composer
f4a0d42363