Skip rubble when locating a city's warehouse building at load

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/engine/db/handlers/dbWarehouseHandler.java

@@ -153,7 +153,7 @@ public class dbWarehouseHandler extends dbHandlerBase {
 
                 // Locate warehouse building
                 for (Building building : city.parentZone.zoneBuildingSet) {
-                    if (building.getBlueprint().getBuildingGroup().equals(mbEnums.BuildingGroup.WAREHOUSE)) {
+                    if (building.getBlueprint().getBuildingGroup().equals(mbEnums.BuildingGroup.WAREHOUSE) && building.getRank() != -1) {
                         city.warehouse.building = building;
                         break;
                     }