- CHANGELOG entry documenting the discovery spine (discover-product, model-domain,
  recommend-architecture, testing-strategy) + 6 test-infra references (based on upstream 1.4.0)
- scripts/sync-upstream.sh — one-command rebrand for cherry-picking upstream changes
- docs/RELEASING.md — lightweight release flow + upstream-sync flow
- version bump 1.4.0 → 1.5.0 (manifests synced); published @therocketcode/gsd-core@1.5.0

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>