A --keep'd isolated stack whose owning process had exited (but whose
containers kept running) was classified 'live' forever and never reaped,
leaking Docker stacks indefinitely. Introduce a start-time-verified
_owner_liveness probe and a new 'kept' state, an ISOLATE_KEEP_TTL (4h,
SHOWCASE_ISOLATE_KEEP_TTL-overridable) that flips an over-age kept slot
to 'stale' so the sweep reclaims it, a com.copilotkit.showcase.isolate
self-id label stamped by apply_isolation, a 'slots --reapable' filter,
and a macOS lsof COMMAND-truncation fix in the own-project port filter.
Real-surface bats cover the liveness false-positive and TTL reaping.
Jordan Ritter