- 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.
- Add minimax to PROVIDERS lists in gui_2.py and app_controller.py
- Add minimax credentials template in ai_client.py
- Implement _list_minimax_models, _classify_minimax_error, _ensure_minimax_client
- Implement _send_minimax with streaming and reasoning support
- Add minimax to send(), list_models(), reset_session(), get_history_bleed_stats()
- Add unit tests in tests/test_minimax_provider.py
ed