The fail-closed owner ladder (#95407) is correct for new sessions, but
legacy unowned rows on registry-topology installs dead-ended in
SessionOwnerResolutionError (reporter's Error B) with their transcripts
fully intact in state.db.
- resolveLegacyOwnerBackfillScope: pick the single-match store for the
server-side owner backfill at enumeration time (serving registered
connection / primary pool); fail closed on multi-candidate topologies.
- maybeBackfillLegacySessionOwners: one-shot per scope per renderer,
fire-and-forget from the #95407 stamp path, logs the stamped count.
- Read-only stored-transcript resume: when session.resume fails closed,
fetch the transcript over id-only REST (ambient first, then registered
backends, read-only probes only) and open the session as a read-only
transcript instead of dead-ending; sends are refused with a notice and
a later successful live resume clears the latch. Wired into the main
pane resume recovery and the session-tile delegate (which now runs the
same fail-closed owner gate as the RPC dispatcher).
Refs #94724
9faa685385