feat(scope): make Belgium and North Sea operational default

backend/app/api/routes/exports.py

@@ -6,6 +6,7 @@ from fastapi import APIRouter, Depends, Query
 from fastapi.responses import FileResponse
 from sqlalchemy.orm import Session
 
+from app.core.errors import AppError
 from app.db.session import get_db
 from app.schemas import Envelope
 from app.schemas.export import (
@@ -47,7 +48,11 @@ def export_geojson(payload: GeoJsonExportRequest, db: Session = Depends(get_db))
         )
     if payload.dataset_id is not None:
         return envelope(ExportService.export_dataset_geojson(db, payload.dataset_id, payload.name).model_dump(mode="json"))
-    return envelope({})
+    raise AppError(
+        code="INVALID_EXPORT_REQUEST",
+        message="GeoJSON export request does not match any supported export target",
+        status_code=422,
+    )
 
 
 @router.post("/metadata", response_model=Envelope[ExportCreateResponse])