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/es.object.get-own-property-descriptors.js

@@ -0,0 +1,25 @@
+'use strict';
+var $ = require('../internals/export');
+var DESCRIPTORS = require('../internals/descriptors');
+var ownKeys = require('../internals/own-keys');
+var toIndexedObject = require('../internals/to-indexed-object');
+var getOwnPropertyDescriptorModule = require('../internals/object-get-own-property-descriptor');
+var createProperty = require('../internals/create-property');
+
+// `Object.getOwnPropertyDescriptors` method
+// https://tc39.es/ecma262/#sec-object.getownpropertydescriptors
+$({ target: 'Object', stat: true, sham: !DESCRIPTORS }, {
+  getOwnPropertyDescriptors: function getOwnPropertyDescriptors(object) {
+    var O = toIndexedObject(object);
+    var getOwnPropertyDescriptor = getOwnPropertyDescriptorModule.f;
+    var keys = ownKeys(O);
+    var result = {};
+    var index = 0;
+    var key, descriptor;
+    while (keys.length > index) {
+      descriptor = getOwnPropertyDescriptor(O, key = keys[index++]);
+      if (descriptor !== undefined) createProperty(result, key, descriptor);
+    }
+    return result;
+  }
+});