chore(deps): bump next from 15.5.8 to 15.5.9 in /core

Bumps [next](https://github.com/vercel/next.js) from 15.5.8 to 15.5.9.
- [Release notes](https://github.com/vercel/next.js/releases)
- [Changelog](https://github.com/vercel/next.js/blob/canary/release.js)
- [Commits](vercel/next.js@v15.5.8...v15.5.9)

---
updated-dependencies:
- dependency-name: next
  dependency-version: 15.5.9
  dependency-type: direct:production
...

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

Author: dependabot[bot]

core/package.json

@@ -57,7 +57,7 @@
     "lodash.debounce": "^4.0.8",
     "lru-cache": "^11.1.0",
     "lucide-react": "^0.474.0",
-    "next": "15.5.8",
+    "next": "15.5.9",
     "next-auth": "5.0.0-beta.30",
     "next-intl": "^4.1.0",
     "nuqs": "^2.4.3",