Bump next in /webapp in the npm_and_yarn group across 1 directory

Bumps the npm_and_yarn group with 1 update in the /webapp directory: [next](https://github.com/vercel/next.js).


Updates `next` from 15.4.10 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@v15.4.10...v16.1.5)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

webapp/package-lock.json

@@ -27,7 +27,7 @@
         "date-fns": "^3.6.0",
         "glob": "^11.1.0",
         "lucide-react": "^0.411.0",
-        "next": "15.4.10",
+        "next": "16.1.5",
         "next-themes": "^0.4.6",
         "react": "19.1.0",
         "react-day-picker": "^9.13.0",