Pins backfill behaviour on postgres:16-alpine (H2 unusable — title is NOT NULL): a stale auto-title is rewritten, the sweep is idempotent (second run touches nothing), prose is left alone, and the mechanical rename adds no document_versions rows. Permission (401/403) stays in the faster @WebMvcTest slice. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>