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/es-abstract/2024/ToDateString.js

@@ -0,0 +1,21 @@
+'use strict';
+
+var GetIntrinsic = require('get-intrinsic');
+
+var $TypeError = require('es-errors/type');
+var $Date = GetIntrinsic('%Date%');
+var $String = GetIntrinsic('%String%');
+
+var $isNaN = require('math-intrinsics/isNaN');
+
+// https://262.ecma-international.org/6.0/#sec-todatestring
+
+module.exports = function ToDateString(tv) {
+	if (typeof tv !== 'number') {
+		throw new $TypeError('Assertion failed: `tv` must be a Number');
+	}
+	if ($isNaN(tv)) {
+		return 'Invalid Date';
+	}
+	return $String(new $Date(tv));
+};