Complete Cocos Creator port with level bundles, themes, and tooling.

Adds level prefabs, theme assets, audio, extensions, and deployment scripts for the Unity WebGL migration.

Co-authored-by: Cursor <cursoragent@cursor.com>

extensions/plugin-import-2x/static/migrate-resources/default-assets-2d/scripts/studio-widget.ts

@@ -0,0 +1,7 @@
+import { Widget, _decorator } from "cc";
+const { ccclass } = _decorator;
+
+@ccclass('StudioWidget')
+export class StudioWidget extends Widget {
+    _validateTargetInDEV() {}
+}