1d931506d6
Restored the released coding-agent changelog sections that the previous pre-publish fix run flattened into Unreleased. The local checkout only had tags through v15.5.15, so fix-changelogs compared against an old tag and promoted entire newly-added release sections. - Kept newly-added release-section hunks out of collectPromotableAddedItemLines so the fixer still promotes individual new items added under an existing released section, but does not rewrite whole release blocks. - Added regression coverage for the release-section case. - Restored the coding-agent changelog history and kept only the #2582 entry under Unreleased. Fixes #2582