Backfills CHANGELOG.md, which was empty despite two prior tags: entries for
0.1.0 (untagged, pinned by commit), 0.2.0, 0.3.0, and this release.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WdVgowYC4LARgvNdNMiuvz