GitHub PR description

Inspect the branch diff, commits, related issue or discussion, tests, docs, and
changesets. When updating a PR, read its current body first.

Write

Fill in .github/pull_request_template.md. Write for a reviewer, not a
changelog:

• Keep the Summary to one short paragraph: usually 2–4 sentences and about
  100 words or fewer.
• Lead with the concrete problem, user need, or decision behind the change;
  follow with the solution and meaningful behavior. Prefer short sentences;
  split independent points rather than combining them into a long sentence.
• Do not list files or narrate commits. Include implementation detail only when
  it is necessary to assess behavior or risk.
• Mention breaking changes, preserved behavior, tradeoffs, scope boundaries,
  follow-ups, or stacked PRs only when they matter to review.
• Link an existing issue or discussion with Closes #N, Related to #N, or an
  equivalent when one exists. Do not create an issue solely for a PR.
• State only validation that actually ran, including limitations or failures.

Preserve the checklist and check only verified items.

Publish

Before publishing, confirm the Summary leads with why the change is needed.
Write the body to a file, then pass it to gh pr create or gh pr edit with
--body-file.