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/2023/thisStringValue.js

@@ -0,0 +1,13 @@
+'use strict';
+
+var $StringValueOf = require('call-bound')('String.prototype.valueOf');
+
+// https://262.ecma-international.org/6.0/#sec-properties-of-the-string-prototype-object
+
+module.exports = function thisStringValue(value) {
+	if (typeof value === 'string') {
+		return value;
+	}
+
+	return $StringValueOf(value);
+};