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
- Transitioned vibe tools to an ephemeral registration model where they are installed only when entering `/vibe` mode and removed upon exit.
- Added `activateVibeTools` and `deactivateVibeTools` methods to `AgentSession` to manage these transient tool registrations.
- Removed vibe tools from the default global tool registry, preventing unnecessary background exposure.
- Improved real-time screen rendering by implementing dynamic builder functions for vibe mode components.
- Optimized cursor and spinner rendering to re-derive state from shared mutable options on every paint.
- Added session snapshotting and improved wait logic to accurately detect settled turns and running sessions.
- Ensured reliable toolset restoration during mode transitions through updated logic and new contract tests.