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/ThisSymbolValue.js

@@ -0,0 +1,20 @@
+'use strict';
+
+var $SyntaxError = require('es-errors/syntax');
+var callBound = require('call-bound');
+
+var $SymbolValueOf = callBound('Symbol.prototype.valueOf', true);
+
+// https://262.ecma-international.org/15.0/#sec-thissymbolvalue
+
+module.exports = function ThisSymbolValue(value) {
+	if (typeof value === 'symbol') {
+		return value;
+	}
+
+	if (!$SymbolValueOf) {
+		throw new $SyntaxError('Symbols are not supported; thisSymbolValue requires that `value` be a Symbol or a Symbol object');
+	}
+
+	return $SymbolValueOf(value);
+};