Add Belgium and North Sea coverage foundation

docs/CODEX_EXECUTION_LOG.md

@@ -1,5 +1,31 @@
 ## Autonomous RC program for Belgium and the Belgian North Sea (2026-07-17)
 
+### RC-4 national and maritime coverage foundation
+
+- Added an independent coverage registry so the exact Sprint 7
+  `grb|osm|manual|fixture` provider contract remains unchanged.
+- Added `GET /api/v1/external/coverage/catalog` and
+  `POST /api/v1/external/coverage/resolve` with canonical envelopes, normalized
+  themes and explicit project-materialization checks.
+- Added `provision_belgium_north_sea_scope.py`. It accepts only the official
+  NGI AdminVector archive, RBINS marine reporting units and the exact 15-layer
+  `imsp26` WFS allowlist. It verifies archive/response limits, safe extraction,
+  layer counts, pagination, geometries and SHA256 evidence.
+- Verified live source contracts from the Codex host: all 15 MSP layers were
+  reachable and returned 101 features in total; the current RBINS reporting
+  units yielded BPNS, territorial sea, EEZ and continental-shelf geometries.
+- The territorial sea is derived only by unioning official 0-1 nm and 1-12 nm
+  units. EEZ and continental shelf retain the same official offshore geometry
+  as separate records with different legal-domain provenance.
+- Frontend startup now prefers a materialized
+  `Belgium and North Sea Workbench`; drawn bboxes receive a compact,
+  zone-split coverage matrix. Existing Mol/Kempen workspaces remain available.
+- Local validation passed 986 backend tests, frontend typecheck/build, the
+  full readiness gate, Alembic head `202607160001`, complete offline migration
+  SQL and live-smoke shell syntax.
+- Tower fetch-only, persistence, live coverage API and browser acceptance are
+  the remaining RC-4 exit evidence.
+
 - Froze the RC geography as all Belgian land plus the separately labelled
   territorial sea, EEZ and continental shelf.
 - Retained Mol and the Kempen as validated regression areas instead of the