feat(release): add contributor-aware release notes workflow

CONTRIBUTING.md

@@ -148,10 +148,15 @@ Generated fixtures and manifests remain ignored.
 Use the [release guide](docs/releasing.md). Main pushes automatically refresh a
 Release Please PR with the next version and changelog. Review its migration
 notes, wait for the current CI checks to pass, and merge it into main to publish.
+
 The Release workflow validates and tags that merge; both publishers build its
 exact SHA. Ordinary main pushes cannot publish packages. An optional manual
 `release/VERSION` checkpoint retains explicit preparation and publication.
 
+For grouped release notes with verified contributor thanks, use the repository's
+`rea-changelog-update` skill in `.agents/skills/rea-changelog-update/`. Its inventory,
+credit checks, and finalization process are described in the release guide.
+
 Keep new implementation commits on main for the next release. The workflow
 owns packaged-artifact verification, npm publication, the published CLI/MCP
 canary, and MCP Registry publication. Sync manual checkpoint metadata back to