fix(deps): update react monorepo to v19

Author: renovate[bot]

package.json

@@ -25,8 +25,8 @@
     "clsx": "^2.1.1",
     "hast-util-is-element": "^3.0.0",
     "prism-react-renderer": "^2.4.1",
-    "react": "18.3.1",
-    "react-dom": "18.3.1",
+    "react": "19.1.1",
+    "react-dom": "19.1.1",
     "rehype-katex": "7.0.1",
     "remark-math": "6.0.0"
   },