chore: bump to next@15.4.0-canary.81 (#10530)

No particular reason, just keeping up to date

Author: mischnic

docs/site/package.json

@@ -49,7 +49,7 @@
     "fumadocs-ui": "^14",
     "geist": "^1.3.0",
     "lucide-react": "^0.479.0",
-    "next": "15.4.0-canary.23",
+    "next": "15.4.0-canary.81",
     "next-themes": "^0.4.6",
     "react": "19.0.0",
     "react-dom": "19.0.0",
@@ -63,8 +63,8 @@
     "zod": "^3.24.2"
   },
   "devDependencies": {
-    "@next/env": "15.4.0-canary.23",
-    "@next/eslint-plugin-next": "15.4.0-canary.23",
+    "@next/env": "15.4.0-canary.81",
+    "@next/eslint-plugin-next": "15.4.0-canary.81",
     "@turbo/eslint-config": "workspace:*",
     "@turbo/tsconfig": "workspace:^",
     "@turbo/types": "workspace:*",