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/uuid/dist/esm-node/validate.js

@@ -0,0 +1,7 @@
+import REGEX from './regex.js';
+
+function validate(uuid) {
+  return typeof uuid === 'string' && REGEX.test(uuid);
+}
+
+export default validate;