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/@istanbuljs/schema/README.md

@@ -0,0 +1,30 @@
+# @istanbuljs/schema
+
+[![Travis CI][travis-image]][travis-url]
+[![NPM Version][npm-image]][npm-url]
+[![NPM Downloads][downloads-image]][downloads-url]
+[![MIT][license-image]](LICENSE)
+
+Schemas describing various structures used by nyc and istanbuljs
+
+## Usage
+
+```js
+const {nyc} = require('@istanbuljs/schema').defaults;
+
+console.log(`Default exclude list:\n\t* ${nyc.exclude.join('\n\t* ')}`);
+```
+
+## `@istanbuljs/schema` for enterprise
+
+Available as part of the Tidelift Subscription.
+
+The maintainers of `@istanbuljs/schema` and thousands of other packages are working with Tidelift to deliver commercial support and maintenance for the open source dependencies you use to build your applications. Save time, reduce risk, and improve code health, while paying the maintainers of the exact dependencies you use. [Learn more.](https://tidelift.com/subscription/pkg/npm-istanbuljs-schema?utm_source=npm-istanbuljs-schema&utm_medium=referral&utm_campaign=enterprise)
+
+[npm-image]: https://img.shields.io/npm/v/@istanbuljs/schema.svg
+[npm-url]: https://npmjs.org/package/@istanbuljs/schema
+[travis-image]: https://travis-ci.org/istanbuljs/schema.svg?branch=master
+[travis-url]: https://travis-ci.org/istanbuljs/schema
+[downloads-image]: https://img.shields.io/npm/dm/@istanbuljs/schema.svg
+[downloads-url]: https://npmjs.org/package/@istanbuljs/schema
+[license-image]: https://img.shields.io/npm/l/@istanbuljs/schema.svg