Bump next from 14.2.21 to 15.2.1 (#41)

Bumps [next](https://github.com/vercel/next.js) from 14.2.21 to 15.2.1.
- [Release notes](https://github.com/vercel/next.js/releases)
- [Changelog](https://github.com/vercel/next.js/blob/canary/release.js)
- [Commits](vercel/next.js@v14.2.21...v15.2.1)

---
updated-dependencies:
- dependency-name: next
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

package-lock.json

@@ -17,7 +17,7 @@
     "gray-matter": "^4.0.3",
     "hast-util-to-string": "^3.0.0",
     "highlight.js": "^11.10.0",
-    "next": "^15.3.1",
+    "next": "^15.3.4",
     "next-themes": "^0.4.6",
     "react": "^19.1.0",
     "react-dom": "^19.1.0",