Separate flood hazards from surface water theme

backend/tests/test_sprint208_vmm_flood_hazard.py

@@ -366,3 +366,5 @@ def test_flood_hazard_runtime_contract_is_packaged() -> None:
     assert "COPY scripts/provision_mol_flood_hazards.py" in dockerfile
     assert "Overstromingsscenario" in frontend
     assert "floodHazardImageUrl" in frontend
+    assert "dataset.source_name === 'vmm_flood_hazard'" in frontend
+    assert "return theme.id === 'flood_hazard'" in frontend

frontend/src/components/map/MapWorkspace.tsx

@@ -147,6 +147,15 @@ function datasetSearchText(dataset: DatasetCreateResponse): string {
 }
 
 function datasetMatchesTheme(dataset: DatasetCreateResponse, theme: DataTheme): boolean {
+  // Governed raster products have one unambiguous semantic theme. Matching
+  // them by generic substrings (for example "water" in "waterdiepte") would
+  // make a flood scenario replace the permanent surface-water layer.
+  if (dataset.source_name === 'vmm_flood_hazard') {
+    return theme.id === 'flood_hazard'
+  }
+  if (dataset.source_name === 'digitaal_vlaanderen_dhmv') {
+    return theme.id === 'elevation'
+  }
   const searchText = datasetSearchText(dataset)
   return theme.tokens.some((token) => searchText.includes(token))
 }