collapsesPeersOnTear

A us.tractat.kuilt.core.SeamState.Torn seam's us.tractat.kuilt.core.Seam.peers is exactly { selfId } — the collapse obligation stated on Seam.peers (#1816).

false means the fabric leaves a remote peer advertised as reachable after it tears (a frozen pre-tear roster, or a shared session registry the closing seam removes itself from), so a decorator that folds member seams — CompositeSeam — reads it as still reachable until the member is detached. Every false here is a bug with a tracking issue, not a by-design gap.