build(deps): bump next from 15.2.4 to 16.1.5 in /frontend

Bumps [next](https://github.com/vercel/next.js) from 15.2.4 to 16.1.5.
- [Release notes](https://github.com/vercel/next.js/releases)
- [Changelog](https://github.com/vercel/next.js/blob/canary/release.js)
- [Commits](vercel/next.js@v15.2.4...v16.1.5)

---
updated-dependencies:
- dependency-name: next
  dependency-version: 16.1.5
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]