Update for simplified client API and add Node.js hosting guide

Changes:
- Update App.jsx to use Rondevu.connect() instead of new + initialize()
- Update publishService to use 'service' parameter instead of 'serviceFqn'
- Remove explicit claimUsername() calls (now implicit)
- Add comprehensive NODE_HOST_GUIDE.md for hosting WebRTC services in Node.js
- Update README with Node.js hosting section

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

package.json

@@ -16,9 +16,7 @@
     "qrcode": "^1.5.4",
     "react": "^18.2.0",
     "react-dom": "^18.2.0",
-    "react-hot-toast": "^2.6.0"
-  },
-  "optionalDependencies": {
+    "react-hot-toast": "^2.6.0",
     "wrtc": "^0.4.7"
   },
   "devDependencies": {