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/regenerator-runtime/README.md

@@ -0,0 +1,31 @@
+# regenerator-runtime
+
+Standalone runtime for
+[Regenerator](https://github.com/facebook/regenerator)-compiled generator
+and `async` functions.
+
+To import the runtime as a module (recommended), either of the following
+import styles will work:
+```js
+// CommonJS
+const regeneratorRuntime = require("regenerator-runtime");
+
+// ECMAScript 2015
+import regeneratorRuntime from "regenerator-runtime";
+```
+
+To ensure that `regeneratorRuntime` is defined globally, either of the
+following styles will work:
+```js
+// CommonJS
+require("regenerator-runtime/runtime");
+
+// ECMAScript 2015
+import "regenerator-runtime/runtime.js";
+```
+
+To get the absolute file system path of `runtime.js`, evaluate the
+following expression:
+```js
+require("regenerator-runtime/path").path
+```