docs: tighten changelog wording for the ls path
Address nh13 review: the workspace-id bullet said the id is checked
"before the push", but ls never pushes - its check runs before the
query; reword to "verified up front". And the ls bullet said stdout
carries "only image references", but the loop also prints the creation
time; reword to "only the image listing".
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
