fix(install): clone function handle undefined

- clone(undefined) now returns undefined instead of throwing JSON.parse error
- This fixes install when plugins.entries.dirigent doesn't exist yet

scripts/install-dirigent-openclaw.mjs

@@ -122,6 +122,7 @@ function findLatestInstallRecord() {
 
 // Deep clone
 function clone(v) {
+  if (v === undefined) return undefined;
   return JSON.parse(JSON.stringify(v));
 }