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/loader-runner/lib/LoaderLoadingError.js

@@ -0,0 +1,11 @@
+"use strict";
+
+class LoadingLoaderError extends Error {
+	constructor(message) {
+		super(message);
+		this.name = "LoaderRunnerError";
+		Error.captureStackTrace(this, this.constructor);
+	}
+}
+
+module.exports = LoadingLoaderError;