A ramp step whose target is below the current actual temperature can
only be reached by ambient cooling - the heater can't actively cool.
SudTask now detects this once per ramp phase and calls the controller's
new set_cooling() override (forces y=0, bypassing the FSM) instead of
waiting for its hysteresis-based IDLE transition. The GUI shows a
blinking blue "Cool down" label in the status bar while this is active.
Progression already only advances once theta_ist matches theta_soll
regardless of direction, so no change was needed there.
jens
1170718c3b