chore(deps): bump next from 14.2.30 to 15.5.15

Bumps [next](https://github.com/vercel/next.js) from 14.2.30 to 15.5.15.
- [Release notes](https://github.com/vercel/next.js/releases)
- [Changelog](https://github.com/vercel/next.js/blob/canary/release.js)
- [Commits](vercel/next.js@v14.2.30...v15.5.15)

---
updated-dependencies:
- dependency-name: next
  dependency-version: 15.5.15
  dependency-type: direct:production
...

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

Author: dependabot[bot]

packages/docs/package.json

@@ -19,7 +19,7 @@
     "react-chartjs-2": "^5.0.0",
     "@octokit/request": "^8.0.0",
     "react-select": "^5.7.0",
-    "next": "^14.0.0",
+    "next": "^15.5.15",
     "nextra": "^2.13.2",
     "nextra-theme-docs": "^2.13.2",
     "react": "^18.0.0",