- validator: reject equipment start/stop when unit auto_enabled
- engine: fix stop_time_sec==0 causing infinite Stopped state (never starts)
- engine: call simulate_run_feedback after auto commands when SIMULATE_PLC=true
- command: extract simulate_run_feedback to shared module (was private in handler)
- web: disable Start/Stop buttons when unit auto is active; sync on WS runtime update
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>