Leaving the lead summary and the upgrade notes to be composed at publish
time put the writing at the worst possible moment — weeks after the changes,
with no review. Both belong in the CHANGELOG entry, which the release PR is
already editing.
The lead needed no code: text between the version heading and the first
group already flowed into the page. The Upgrade group did — CI appended its
own `## Upgrade`, so a CHANGELOG that carried upgrade notes produced two
headings. The group is now lifted out and the boilerplate wrapped around it,
pip line above, compare link below, matching every page since 1.1.3.
Publishing is now a read-through and a click.
Co-authored-by: zhanghui <zhanghui@shanda.com>
Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>
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