doc(demo): React 19 rc 1 for nextjs demo

Author: ntucker

examples/nextjs/package-lock.json

@@ -20,8 +20,8 @@
     "@types/react-dom": "npm:[email protected]",
     "clsx": "^2.1.1",
     "next": "15.0.3",
-    "react": "19.0.0-rc-69d4b800-20241021",
-    "react-dom": "19.0.0-rc-69d4b800-20241021",
+    "react": "19.0.0-rc.1",
+    "react-dom": "19.0.0-rc.1",
     "tar-fs": "^3.0.6",
     "tunnel-agent": "^0.6.0",
     "typescript": "^5.4.5"