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/modules/es.object.create.js

@@ -0,0 +1,11 @@
+'use strict';
+// TODO: Remove from `core-js@4`
+var $ = require('../internals/export');
+var DESCRIPTORS = require('../internals/descriptors');
+var create = require('../internals/object-create');
+
+// `Object.create` method
+// https://tc39.es/ecma262/#sec-object.create
+$({ target: 'Object', stat: true, sham: !DESCRIPTORS }, {
+  create: create
+});