Add Belgium and North Sea coverage foundation

docs/DATA_SOURCES.md

@@ -719,6 +719,42 @@ the canonical vector persistence path for Mol and Kempen. Additional Flemish
 vector themes still require governed regional operators; a catalogue record
 alone never makes them operational.
 
+## Belgium and Belgian North Sea scope foundation
+
+The release-candidate workbench uses two distinct registries:
+
+- the fixed Sprint 7 import-provider registry for `grb`, `osm`, `manual` and
+  `fixture`;
+- the national coverage registry for audited source authority and actual
+  project materialization by theme and zone.
+
+The explicit operator
+`scripts/provision_belgium_north_sea_scope.py` downloads the official NGI
+AdminVector EPSG:4326 GeoPackage archive, verifies size and archive safety,
+requires the territory, maritime zone, region, province and municipality
+layers, and retains archive/GeoPackage/artifact checksums. NGI output is
+licensed CC BY 4.0 and persists as reference Datasets through
+`DatasetService`.
+
+The same operator obtains the RBINS/BMDC
+`od_nature:marine_reporting_units_2024` WFS layer. The territorial sea is the
+union of official 0-1 nm coastal waters and 1-12 nm territorial waters. The
+official offshore-beyond-12-nm geometry is persisted twice only to preserve
+the distinct legal semantics of the EEZ water column and continental-shelf
+seabed/subsoil. This is explicit provenance-preserving derivation, not
+invented geometry.
+
+The legally current Belgian Marine Spatial Plan 2026-2034 is fetched from the
+fixed `imsp26` WFS allowlist and retained as one versioned reference Dataset.
+No live vessel activity, depth, water volume or other unsupported metric is
+inferred from these plan zones.
+
+The coverage resolver reports a theme `operational` only when a matching
+`ready` Dataset exists in the selected project. Implemented acquisition
+without project materialization is `partial`; Walloon, Brussels, Statbel and
+MDK families remain `not_configured` until their own bounded adapters and
+source-specific metric contracts are implemented.
+
 ## Bathymetry, inland profiles and maritime scope
 
 The official VHA Digital Atlas profile-point layer is the first operational