Introduces the release-changelog skill (skills/release-changelog/SKILL.md) that teaches agents to generate user-facing changelogs from git history, changesets, and merged PRs. Includes breaking change detection, categorization heuristics, and structured markdown output template. Also creates the releases/ directory convention for storing versioned release notes. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>