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-pure/modules/esnext.weak-map.delete-all.js

@@ -0,0 +1,18 @@
+'use strict';
+var $ = require('../internals/export');
+var aWeakMap = require('../internals/a-weak-map');
+var remove = require('../internals/weak-map-helpers').remove;
+
+// `WeakMap.prototype.deleteAll` method
+// https://github.com/tc39/proposal-collection-methods
+$({ target: 'WeakMap', proto: true, real: true, forced: true }, {
+  deleteAll: function deleteAll(/* ...elements */) {
+    var collection = aWeakMap(this);
+    var allDeleted = true;
+    var wasDeleted;
+    for (var k = 0, len = arguments.length; k < len; k++) {
+      wasDeleted = remove(collection, arguments[k]);
+      allDeleted = allDeleted && wasDeleted;
+    } return !!allDeleted;
+  }
+});