feat(geoportal): OpenFreeMap vector basemaps + eTerra ORTO 2024 ortophoto

Basemap options:
- Liberty (OpenFreeMap vector) — default, sharp vector tiles
- Dark (OpenFreeMap) — dark theme, auto-styled
- Satellite (ESRI World Imagery) — raster
- ANCPI Ortofoto 2024 — proxied via /api/eterra/tiles/orto, converts
  Web Mercator z/x/y to EPSG:3844 bbox, authenticates with eTerra
  session, caches 24h. Requires ETERRA_USERNAME/PASSWORD env vars.

Replaces old raster OSM/OpenTopoMap with vector styles.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/modules/geoportal/components/geoportal-module.tsx

@@ -40,7 +40,7 @@ export function GeoportalModule() {
   const mapHandleRef = useRef<MapViewerHandle>(null);
 
   // Map state
-  const [basemap, setBasemap] = useState<BasemapId>("osm");
+  const [basemap, setBasemap] = useState<BasemapId>("liberty");
   const [layerVisibility, setLayerVisibility] = useState<LayerVisibility>(
     getDefaultVisibility
   );