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/TimeString.js

@@ -0,0 +1,26 @@
+'use strict';
+
+var $TypeError = require('es-errors/type');
+
+var $isNaN = require('math-intrinsics/isNaN');
+
+var HourFromTime = require('./HourFromTime');
+var MinFromTime = require('./MinFromTime');
+var SecFromTime = require('./SecFromTime');
+var ToZeroPaddedDecimalString = require('./ToZeroPaddedDecimalString');
+
+// https://262.ecma-international.org/13.0/#sec-timestring
+
+module.exports = function TimeString(tv) {
+	if (typeof tv !== 'number' || $isNaN(tv)) {
+		throw new $TypeError('Assertion failed: `tv` must be a non-NaN Number');
+	}
+
+	var hour = ToZeroPaddedDecimalString(HourFromTime(tv), 2); // step 1
+
+	var minute = ToZeroPaddedDecimalString(MinFromTime(tv), 2); // step 2
+
+	var second = ToZeroPaddedDecimalString(SecFromTime(tv), 2); // step 3
+
+	return hour + ':' + minute + ':' + second + ' GMT'; // step 4
+};