ClaimLost

The run lost its claim on the thread, so it stopped: its lease passed with no renewal landing (the run judges this itself, by its own monotonic clock), a renewal was refused (StaleClaim), or the store refused one of its commits as stale. The run commits nothing more - not even a RunFailed - and drops what it had not yet written; whatever it made durable before stands. token is the run's own claim, and current the thread's current claim when the store named one: another run then holds the thread. None means the store named none - the run judged its lease passed without asking it, or the store found no current claim (a successor that took over has since released it). A failure the run was recording when its commit was refused is logged, not carried. Unlike CheckpointWriteFailed, it is not a store outage. recover may be attempted once the thread is free: it is refused with ThreadBusy while a successor holds the thread, so retry; a successor that finished the work leaves the thread's state showing it (NothingToRecover); and a lease that lapsed with no successor leaves the last checkpoint Running, which recover continues.