Github proof is a bit clunky with the cli

It's difficult to copy from the terminal in some cases. Maybe have it require qn output file by default so that there is no confusion or make the --output flag more prominant?

Start by reproducing the GitHub proof flow through the CLI and compare the current terminal-copy experience with the qn output-file and --output suggestions in the issue. No files or tests are identified; the work is done when one concrete behavior is chosen and the resulting CLI flow avoids the described confusion.

Written by the indexing model from the issue text.