### Added
- `tools/update_gitea_releases.py`: one-shot script to backfill Gitea release bodies with CHANGELOG content via the Gitea API
- `tools/release-notes/`: per-version Markdown snippets used by the backfill script

### Changed
- Release workflow now extracts the relevant CHANGELOG section and uses it as the GitHub Release body (`body_path`)
- Release workflow adds a step to update the corresponding Gitea release body via API (`GITEA_TOKEN` secret)
- All GitHub Actions upgraded to node24-native major versions (no more Node 20 deprecation warnings)
