feat: add native road compiler provider

scripts/lib/area-config.js

@@ -117,6 +117,7 @@ function normalizeAreaConfig(raw, options = {}) {
     blender: {
       treeStyle: raw.blender?.treeStyle || "natural",
       officeOverrides: raw.blender?.officeOverrides || raw.blender?.office_overrides || "",
+      roadProvider: roadProviderOption(raw.blender?.roadProvider),
     },
     compress,
     budget,
@@ -172,6 +173,14 @@ function numberOption(value, fallback, label, min, max) {
   return number;
 }
 
+function roadProviderOption(value) {
+  const provider = value ?? "osm2streets";
+  if (provider !== "osm2streets" && provider !== "native") {
+    throw new Error("blender.roadProvider must be \"osm2streets\" or \"native\".");
+  }
+  return provider;
+}
+
 function integerOption(value, fallback, label) {
   const number = value === undefined ? fallback : Number(value);
   if (!Number.isInteger(number) || number < 1) {