Bump next from 15.3.5 to 15.5.2

Bumps [next](https://github.com/vercel/next.js) from 15.3.5 to 15.5.2.
- [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/v15.3.5...v15.5.2)

---
updated-dependencies:
- dependency-name: next
  dependency-version: 15.5.2
  dependency-type: direct:production
...

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

package.json

@@ -14,7 +14,7 @@
     "@vercel/speed-insights": "^1.2.0",
     "cross-env": "^7.0.3",
     "katex": "^0.16.22",
-    "next": "^15.3.5",
+    "next": "^15.5.2",
     "next-sitemap": "^4.2.3",
     "nextra": "^4.2.17",
     "nextra-theme-docs": "^4.2.17",