Federate official Belgium data sources

backend/README.md

@@ -1854,21 +1854,25 @@ readiness state such as TLS or endpoint failure. Runtime controls are
 `MDK_BATHYMETRY_PROBE_TIMEOUT_SECONDS` and
 `MDK_BATHYMETRY_PROBE_MAX_RESPONSE_MB`. TLS verification cannot be disabled.
 
-## Governed forest, agriculture, nature and soil acquisition
+## Governed regional official-vector acquisition
 
 The thematic raster registry includes forest and agricultural land-use masks
 derived from Landgebruik Vlaanderen 2025 classes 12 and 13/14. They use the
 existing thematic acquisition and selection routes.
 
-Two polygon products are exposed through
+Eight fixed products are exposed through
 `/datasets/official-vector/products` and
-`/datasets/official-vector/acquire`: INBO BWK/Natura 2000 2025 and the DOV
-digital soil map. Both require an EPSG:4326 rectangle, optionally intersect it
-with a persisted Area, clip in EPSG:31370 and persist through
-`DatasetService.import_vector_bytes`.
+`/datasets/official-vector/acquire`: INBO BWK/Natura 2000 2025 and DOV soil
+for Flanders; PICC buildings, roads, hydrographic axes and surfaces for
+Wallonia; and UrbIS buildings and cadastral parcels for Brussels. All require
+an EPSG:4326 rectangle, clip in a provider-appropriate metric CRS and persist
+through `DatasetService.import_vector_bytes`. SPW/PICC and UrbIS additionally
+require a persisted exact regional coverage Area and never write directly to
+`vector_features`.
 
 Runtime controls are `OFFICIAL_VECTOR_ENABLED`, `BWK_WFS_URL`,
-`DOV_SOIL_WFS_URL`, `OFFICIAL_VECTOR_MIN_SIDE_M`,
+`DOV_SOIL_WFS_URL`, `SPW_PICC_ENABLED`, `SPW_PICC_MAPSERVER_URL`,
+`URBIS_ENABLED`, `URBIS_WFS_URL`, `OFFICIAL_VECTOR_MIN_SIDE_M`,
 `OFFICIAL_VECTOR_MAX_SIDE_M`, `OFFICIAL_VECTOR_PAGE_SIZE`,
 `OFFICIAL_VECTOR_MAX_PAGES`, `OFFICIAL_VECTOR_MAX_FEATURES`,
 `OFFICIAL_VECTOR_TIMEOUT_SECONDS`, `OFFICIAL_VECTOR_MAX_RESPONSE_MB`,