Vibe worker roster lived only in a process-local Map, so a resumed parent
session started with an empty registry and vibe_send failed with
"Unknown vibe session". Persist a versioned, parent-scoped lifecycle
journal (spawn/turn/tombstone events), rehydrate validated idle workers
through the persisted-subagent reviver on resume, and gate the flow with
generation/CAS protection so stale finalizers cannot clobber a
replacement worker. Killed transcripts stay readable but non-revivable;
mode-exit commits tombstones atomically with the mode change and rolls
back cleanly on storage failure.
Ported from @mastertyko's fork branch fix/vibe-session-persistence.
Fixes#5303
- Fixed cold revival flow so parked subagents are restored from persisted sessions at startup.
- Fixed session-init persistence to include spawns and readSummarize fields for replay accuracy.
- Fixed latest-session lookup by adding peekSessionInit for lock-free persisted contract access.
- Added lifecycle and session tests for cold-revive success, decline, and retry paths.
Introduces AgentLifecycleManager: when the task executor adopts a finished subagent the manager arms a TTL timer on idle, parks the agent on expiry (disposes the live session, keeps the AgentRef + sessionFile), and revives it on demand via an injected reviver. Only this manager flips parked ↔ idle. AgentRegistry now annotates session: AgentRef["session"] as null exactly when parked/aborted, and sdk.ts wires the lifecycle dispose into main-session teardown, derives agentKind once, and gates ref unregistration on parking so a parked agent stays addressable (history://, revive).
roboomp