Print each Sud step's number and description in the demo

Makes it easier to follow which schedule step is currently active
when watching the demo run.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CgR9tPaSzFkAwRAUyeaaCD

scripts/demos/sud/demo_sud.py

@@ -67,6 +67,7 @@ if __name__ == '__main__':
 
 	def on_step_changed(step):
 		if step is not None:
+			print(f"Step {step['number']}: {step['descr']}")
 			if 'ramp' in step:
 				ctrl.set_theta_soll(step['ramp']['temp'])
 				ctrl.set_heatrate_soll(step['ramp']['rate'])