- Add `rem_local: bool` to UnitRuntime; set true when any equipment's
REM signal is false with good quality
- Engine check_fault_comm: stop auto-control and fire AutoControlStopped
when any equipment switches to local mode
- Block start-auto when rem_local (backend + error message)
- Frontend: disable Start Auto button in units/ops views when rem_local
- Frontend: disable equipment Start/Stop buttons in config view when
unit's rem_local is true
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>