Background processes spawned with terminal(background=true) are killed from
three agent-lifecycle sweeps: agent release()'s kill_all, a gateway turn
timeout's kill_started_since, and agent close's owned-process loop. Jobs the
user explicitly wants to outlive the session (overnight batches, watchful
daemons) had no way to opt out.
Add terminal(background=true, persist_on_release=true):
- ProcessSession.persist_on_release, stamped by spawn_local/spawn_via_env,
carried in crash-recovery checkpoints and exposed via list_sessions()
- kill_all skips persisted sessions only for lifecycle sources
(_LIFECYCLE_KILL_SOURCES: kill_all, gateway_turn_timeout, agent_close);
explicit operator stops (process_manage kill, /stop slash + RPC mirror,
CLI /stop) now pass distinct sources so they still reach persisted jobs
- the agent_close owned-process loop in _close_task_resources skips
persisted sessions the same way
- gateway shutdown keeps killing persisted jobs (source=gateway_shutdown):
the host is going away and survivors would become PPID=1 orphans
Co-authored-by: salvaged from #109846 (persist_on_release plumbing) and
extended to the turn-timeout and agent_close paths.
ec5c9c738a