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/IsIntegralNumber.js

@@ -0,0 +1,14 @@
+'use strict';
+
+var truncate = require('./truncate');
+
+var $isFinite = require('math-intrinsics/isFinite');
+
+// https://262.ecma-international.org/14.0/#sec-isintegralnumber
+
+module.exports = function IsIntegralNumber(argument) {
+	if (typeof argument !== 'number' || !$isFinite(argument)) {
+		return false;
+	}
+	return truncate(argument) === argument;
+};