docs(accuracy): retain phase 2 provenance evidence

docs/CODEX_EXECUTION_LOG.md

@@ -12308,3 +12308,56 @@ Open:
   `docs/accuracy-program/06-implementation-roadmap.md`: fix CRS/authority/
   coverage/lineage and protected-test isolation, complete human corpus review,
   rebuild independent data, freeze metrics, then train on `cuda:0`.
+
+## 2026-08-01 - Accuracy Improvement Program Phase 2 source and provenance foundation
+
+### Implemented and verified scope
+
+- Added a server-owned source registry, immutable snapshots, source policies,
+  dataset/dataset-version provenance fields, lineage edges and durable
+  quarantine records through Alembic revision `202608010001`.
+- Added versioned vector, raster, YOLO label and PyTorch model contracts with
+  checksum, CRS, bounds, units, resolution, topology, required attributes,
+  time/freshness and lineage checks. Governed ingestion is idempotent through
+  ingest keys, can safely replay an identical immutable snapshot across
+  projects without rewriting its first fetch time, and fails closed into
+  quarantine when a contract fails.
+- Non-WGS84 vector imports now store the exact transformed EPSG:4326 bytes as
+  the checksummed consumption artifact; original source bytes are retained
+  only as provenance evidence. Vector operations verify both storage CRS and
+  byte checksum before reading a dataset.
+- Enforced a consumption boundary for production inference, primary reference
+  QA, derived work, export, coverage and training inputs. GRB is task-bounded
+  primary authority for suitable Flemish building validation; the Buildings
+  Register, DHMV, Sentinel-2 and OSM retain distinct roles, and OSM cannot
+  become automatic truth.
+- Production detection/segmentation now resolves model sidecar UUIDs against
+  the registry and snapshot database records before adapter loading, including
+  source/snapshot relationship, freshness, quarantine, checksum and version
+  checks. A structural sidecar alone remains catalogue/preflight evidence.
+- Verified the migration in a disposable PostGIS database: upgrade, real
+  trigger-guard DML checks and downgrade passed. This was not a production
+  migration or deployment.
+
+### Evidence and test result
+
+- Retained proof is under `artifacts/evidence/accuracy/P2/`: the source/
+  contract inventory contains 40 server-owned definitions and the PostGIS
+  guard report covers immutable source/snapshot evidence, exact checksum
+  binding, lineage cycles and transitive quarantine propagation.
+- A final cohesive source-to-training regression set passed 221 tests,
+  including immutable snapshot replay, canonical CRS/checksum storage and
+  database-bound model provenance. The governed golden QA benchmark passed.
+- Frontend typecheck, 51 frontend unit tests and production build passed.
+  The complete backend suite now collects but is not green: 1,282 passed and
+  17 failed. Sixteen failures are historical source-text assertions; one is
+  an intermittent Windows WSL-backed `bash.exe` host failure in a syntax test
+  that passes in isolation. Repository Ruff still has 95 findings and
+  `npm run lint` is still absent.
+
+### Decision
+
+- The source/provenance foundation is implemented and verified in a
+  disposable environment, but Phase 2 remains **in progress** and Phase 3 is
+  **not ready**. No training, protected-test release, promotion, national
+  validation or production migration is authorized by this result.