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/2016/IsRegExp.js

@@ -0,0 +1,25 @@
+'use strict';
+
+var GetIntrinsic = require('get-intrinsic');
+
+var $match = GetIntrinsic('%Symbol.match%', true);
+
+var hasRegExpMatcher = require('is-regex');
+var isObject = require('es-object-atoms/isObject');
+
+var ToBoolean = require('./ToBoolean');
+
+// https://262.ecma-international.org/6.0/#sec-isregexp
+
+module.exports = function IsRegExp(argument) {
+	if (!isObject(argument)) {
+		return false;
+	}
+	if ($match) {
+		var isRegExp = argument[$match];
+		if (typeof isRegExp !== 'undefined') {
+			return ToBoolean(isRegExp);
+		}
+	}
+	return hasRegExpMatcher(argument);
+};