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/2021/BinaryXor.js

@@ -0,0 +1,12 @@
+'use strict';
+
+var $TypeError = require('es-errors/type');
+
+// https://262.ecma-international.org/11.0/#sec-binaryxor
+
+module.exports = function BinaryXor(x, y) {
+	if ((x !== 0 && x !== 1) || (y !== 0 && y !== 1)) {
+		throw new $TypeError('Assertion failed: `x` and `y` must be either 0 or 1');
+	}
+	return x ^ y;
+};