refactor: simplify plugin dependency handling

Simplify plugin installation and runtime loading around package-manager-owned dependencies, with Jiti reserved for local/TS fallback paths.

Also scans npm plugin install roots so hoisted transitive dependencies are covered by dependency denylist and node_modules symlink checks.

scripts/lib/optional-bundled-clusters.mjs

@@ -35,7 +35,14 @@ export function hasReleasedBundledInstall(packageJson) {
   );
 }
 
+export function isExplicitlyDownloadablePlugin(packageJson) {
+  return packageJson?.openclaw?.bundle?.includeInCore === false;
+}
+
 export function shouldBuildBundledCluster(cluster, env = process.env, options = {}) {
+  if (isExplicitlyDownloadablePlugin(options.packageJson)) {
+    return false;
+  }
   if (hasReleasedBundledInstall(options.packageJson)) {
     return true;
   }