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/core-js/internals/get-async-iterator.js

@@ -0,0 +1,15 @@
+'use strict';
+var call = require('../internals/function-call');
+var AsyncFromSyncIterator = require('../internals/async-from-sync-iterator');
+var anObject = require('../internals/an-object');
+var getIterator = require('../internals/get-iterator');
+var getIteratorDirect = require('../internals/get-iterator-direct');
+var getMethod = require('../internals/get-method');
+var wellKnownSymbol = require('../internals/well-known-symbol');
+
+var ASYNC_ITERATOR = wellKnownSymbol('asyncIterator');
+
+module.exports = function (it, usingIterator) {
+  var method = arguments.length < 2 ? getMethod(it, ASYNC_ITERATOR) : usingIterator;
+  return method ? anObject(call(method, it)) : new AsyncFromSyncIterator(getIteratorDirect(getIterator(it)));
+};