ac0b564c02
- self.engine was a single ConductorEngine reference that got overwritten when multiple tracks ran concurrently, orphaning the first track's engine - Now uses self.engines: Dict[str, ConductorEngine] keyed by track.id - Updated _spawn_worker, kill_worker, pause_mma, resume_mma, approve_ticket, _load_active_tickets, and _update_ticket_depends_on to use engines.get(track_id) Fixes concurrent MMA track execution bug where only one worker ever appeared.