fix: accept regional layer CLI lists

backend/tests/test_sprint191_regional_grb_context.py

@@ -59,6 +59,19 @@ def test_layer_registry_matches_verified_official_grb_collections() -> None:
         operator.selected_definitions("buildings")
 
 
+def test_layer_selection_accepts_space_and_comma_cli_forms() -> None:
+    operator = load_operator()
+
+    assert [item.key for item in operator.selected_definitions(["roads", "water", "parcels"])] == [
+        "roads",
+        "water",
+        "parcels",
+    ]
+    assert [item.key for item in operator.selected_definitions("roads,parcels")] == ["roads", "parcels"]
+    with pytest.raises(ValueError, match="Unsupported layers"):
+        operator.selected_definitions(["roads", "imaginary"])
+
+
 def test_line_owner_uses_intersection_length_and_deterministic_tie_break() -> None:
     operator = load_operator()
     scopes = __import__("geographic_scopes")