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
- Added `fix:changelogs` npm script backed by `scripts/fix-changelogs.ts`.
- Detects items added to released sections since the latest tag and moves them to `[Unreleased]`.
- Merges duplicate and removes empty `###` category headings as a side effect.
- Supports `--dry-run`, `--check`, and `--since` CLI flags.
roboomp