Adds HeaterTask.shutdown() which switches to open-loop at power 0,
disables TC, and broadcasts ClosedLoop=false to clients so the browser
checkbox unchecks immediately. SudTask fires it via a new set_on_end()
callback whenever state reaches DONE or IDLE, giving both a completed
schedule and a manual Stop the same safe behaviour: stirrer and heater
both off, no heater left running unattended.
Re-enabling after shutdown: check the closed-loop checkbox (sends
ClosedLoop=true → TC re-enabled) or adjust the power slider directly;
the next brew's Play press already sends ClosedLoop=true automatically.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SH2D4LRuCnhLSzoYerAfJX
jensandClaude Sonnet 4.6
6d481d7764