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/SpeciesConstructor.js

@@ -0,0 +1,32 @@
+'use strict';
+
+var GetIntrinsic = require('get-intrinsic');
+
+var $species = GetIntrinsic('%Symbol.species%', true);
+var $TypeError = require('es-errors/type');
+var isObject = require('es-object-atoms/isObject');
+
+var IsConstructor = require('./IsConstructor');
+
+// https://262.ecma-international.org/6.0/#sec-speciesconstructor
+
+module.exports = function SpeciesConstructor(O, defaultConstructor) {
+	if (!isObject(O)) {
+		throw new $TypeError('Assertion failed: Type(O) is not Object');
+	}
+	var C = O.constructor;
+	if (typeof C === 'undefined') {
+		return defaultConstructor;
+	}
+	if (!isObject(C)) {
+		throw new $TypeError('O.constructor is not an Object');
+	}
+	var S = $species ? C[$species] : void 0;
+	if (S == null) {
+		return defaultConstructor;
+	}
+	if (IsConstructor(S)) {
+		return S;
+	}
+	throw new $TypeError('no constructor found');
+};