feat: add official modern Mol land-use series

docs/DATASET_STRATEGY.md

@@ -61,6 +61,33 @@ OSM is used for fast, broad, fallback context.
 ### OSM caveat
 OSM is community-maintained and may be incomplete. UI and reports must describe it as contextual/fallback data, not official ground truth.
 
+## Official modern land-use strategy
+
+The Departement Omgeving version 3 land-use maps are the authoritative modern
+source series for categorical land use. GeoIntel retrieves only explicit
+boundary subsets from MercatorNet WCS; no whole-Flanders raster is fetched at
+startup or during an interactive map query.
+
+- Source years: 2013, 2016, 2019, 2022 and 2025.
+- Native representation: one integer category per 10 m cell in EPSG:31370.
+- Preserved evidence: raw GeoTIFF, WCS request, catalogue URL, checksum, class
+  histogram and processing manifest.
+- Operational representation: source cells polygonized in EPSG:31370, clipped
+  to the requested boundary and normalized to EPSG:4326 `vector_features`.
+- Boundary behavior: retain every source cell touching the boundary, then
+  perform the exact metric geometry intersection; exclude and report NoData.
+- Selection metric: exact polygon intersection area within the source's 10 m
+  representation, reported in hectares with a non-cadastral warning.
+- Identity: raster polygons are not stable source objects; temporal object
+  lineage is unavailable.
+
+Modern land-use series must remain separate from the 1778, 1873 and 1969
+historical cartographic series. Comparisons are valid within each persisted
+series and must retain the source methodology warning. Extension from Mol to
+Kempen reuses the same operator with an explicit approved boundary, project,
+area and scope key; an ambiguous regional label is never converted into an
+invented boundary.
+
 ## User-uploaded raster strategy
 V1 must support controlled local datasets because public raster access and model compatibility can be difficult.