Update PR Description

Workflow

1. Resolve the PR. Use the number/URL the user provided. If none, look up the PR for the current branch with gh pr view.
2. Gather evidence:
   • gh pr view <pr> --json title,body
   • gh pr view <pr> --json commits (commit messages)
   • gh pr diff <pr> (full diff against base)
3. Evaluate divergence. Compare the stated title/description against what the commits and diff actually do. Only flag meaningful divergence (wrong scope, missing major changes, stale claims, inaccurate summary). Ignore trivial wording.
4. Report. Tell the user whether the title and/or description meaningfully diverges. If not, stop here.
5. Suggest iteratively. Propose concrete updated title/description. Ask the user one change at a time whether to apply, accept edits, and refine.
6. Apply. Once agreed, update on the user's behalf with gh pr edit <pr> --title ... --body ....

Notes

• Match the repository's existing PR template/style if the body uses one.
• Don't rewrite a description that's already accurate.
• Update the state of checkboxes where appropriate.
• Remove section placeholders/reminders when filling out a section.
• Do not remove the canary release section.