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/jest-snapshot/build/plugins.js

@@ -0,0 +1,48 @@
+'use strict';
+
+Object.defineProperty(exports, '__esModule', {
+  value: true
+});
+exports.getSerializers = exports.addSerializer = void 0;
+
+var _prettyFormat = require('pretty-format');
+
+var _mockSerializer = _interopRequireDefault(require('./mockSerializer'));
+
+function _interopRequireDefault(obj) {
+  return obj && obj.__esModule ? obj : {default: obj};
+}
+
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+const {
+  DOMCollection,
+  DOMElement,
+  Immutable,
+  ReactElement,
+  ReactTestComponent,
+  AsymmetricMatcher
+} = _prettyFormat.plugins;
+let PLUGINS = [
+  ReactTestComponent,
+  ReactElement,
+  DOMElement,
+  DOMCollection,
+  Immutable,
+  _mockSerializer.default,
+  AsymmetricMatcher
+]; // Prepend to list so the last added is the first tested.
+
+const addSerializer = plugin => {
+  PLUGINS = [plugin].concat(PLUGINS);
+};
+
+exports.addSerializer = addSerializer;
+
+const getSerializers = () => PLUGINS;
+
+exports.getSerializers = getSerializers;