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/react-is/package.json

@@ -0,0 +1,27 @@
+{
+  "name": "react-is",
+  "version": "17.0.2",
+  "description": "Brand checking of React Elements.",
+  "main": "index.js",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/facebook/react.git",
+    "directory": "packages/react-is"
+  },
+  "keywords": [
+    "react"
+  ],
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/facebook/react/issues"
+  },
+  "homepage": "https://reactjs.org/",
+  "files": [
+    "LICENSE",
+    "README.md",
+    "build-info.json",
+    "index.js",
+    "cjs/",
+    "umd/"
+  ]
+}