SyncClampZones returned early when the empty target already held exactly the
solved reduced zones, and otherwise preferred the target's own rail over the
stock's, so a removal committed onto such a sheet kept no rail, removed ids
or time. The stock's rail now wins, and the rail/removal state is reconciled
even when the zones themselves need no replacement.
PM 60f7a673-455e-4a87-b865-a4806f417ee6