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-jasmine2/build/expectationResultFactory.d.ts

@@ -0,0 +1,16 @@
+/**
+ * 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.
+ */
+import type { FailedAssertion } from '@jest/test-result';
+export declare type Options = {
+    matcherName: string;
+    passed: boolean;
+    actual?: any;
+    error?: any;
+    expected?: any;
+    message?: string | null;
+};
+export default function expectationResultFactory(options: Options, initError?: Error): FailedAssertion;