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/workbox-navigation-preload/enable.d.ts

@@ -0,0 +1,13 @@
+import './_version.js';
+/**
+ * If the browser supports Navigation Preload, then this will enable it.
+ *
+ * @param {string} [headerValue] Optionally, allows developers to
+ * [override](https://developers.google.com/web/updates/2017/02/navigation-preload#changing_the_header)
+ * the value of the `Service-Worker-Navigation-Preload` header which will be
+ * sent to the server when making the navigation request.
+ *
+ * @memberof workbox-navigation-preload
+ */
+declare function enable(headerValue?: string): void;
+export { enable };