Initial commit: Developer Tools MVP with visual editor

- Complete React app with 7 developer tools
- JSON Tool with visual structured editor
- Serialize Tool with visual structured editor
- URL, Base64, CSV/JSON, Beautifier, Diff tools
- Responsive navigation with dropdown menu
- Dark/light mode toggle
- Mobile-responsive design with sticky header
- All tools working with copy/paste functionality

node_modules/core-js-pure/modules/esnext.async-iterator.to-array.js

@@ -0,0 +1,11 @@
+'use strict';
+var $ = require('../internals/export');
+var $toArray = require('../internals/async-iterator-iteration').toArray;
+
+// `AsyncIterator.prototype.toArray` method
+// https://github.com/tc39/proposal-async-iterator-helpers
+$({ target: 'AsyncIterator', proto: true, real: true, forced: true }, {
+  toArray: function toArray() {
+    return $toArray(this, undefined, []);
+  }
+});