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/@babel/plugin-transform-async-to-generator/README.md

@@ -0,0 +1,19 @@
+# @babel/plugin-transform-async-to-generator
+
+> Turn async functions into ES2015 generators
+
+See our website [@babel/plugin-transform-async-to-generator](https://babeljs.io/docs/babel-plugin-transform-async-to-generator) for more information.
+
+## Install
+
+Using npm:
+
+```sh
+npm install --save-dev @babel/plugin-transform-async-to-generator
+```
+
+or using yarn:
+
+```sh
+yarn add @babel/plugin-transform-async-to-generator --dev
+```