Summary

Add debugging and minor cleanup to the elegant step-down implementation in test/format to improve observability without changing behavior.

Proposed change

• add targeted debug logging around the step-down sequence
• clean up comments and naming where helpful
• preserve existing behavior and test coverage
• Explicitely turn off prepare and truncate with elegant stepdown internally in test format with a WARNING message.
• Add a new trace_ function that prints the message and a new line that stays on the terminal.

Expected outcome

Make the step-down flow easier to debug and maintain with no intended functional change.