13fa057. Phase 4 established the core vertical proof: teach → persist → close → fresh-session recall → explain → correct → preserved SUPERSEDED predecessor → current ACTIVE result.
T01–T09, T15/T16, D10/D11, and clean-environment deployment passed. The API stayed loopback-only and PostgreSQL remained internal. Backup/isolated restore verified both current and historical lineage. See defects and docs/evidence/phase-4/2026-09-10-text-learning-spine/results.md.