chore(deps): bump next from 16.2.5 to 16.2.6 in /frontend (#251)

Bumps [next](https://github.com/vercel/next.js) from 16.2.5 to 16.2.6.
- [Release notes](https://github.com/vercel/next.js/releases)
- [Changelog](https://github.com/vercel/next.js/blob/canary/release.js)
- [Commits](https://github.com/vercel/next.js/compare/v16.2.5...v16.2.6)

---
updated-dependencies:
- dependency-name: next
  dependency-version: 16.2.6
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

frontend/package.json

@@ -14,7 +14,7 @@
     "@tanstack/react-query": "^5.99.0",
     "axios": "^1.15.0",
     "lucide-react": "^1.8.0",
-    "next": "16.2.5",
+    "next": "16.2.6",
     "react": "19.2.5",
     "react-dom": "19.2.5",
     "zustand": "^5.0.12"