chore(deps): bump next from 15.3.0 to 15.4.8

Bumps [next](https://github.com/vercel/next.js) from 15.3.0 to 15.4.8.
- [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/v15.3.0...v15.4.8)

---
updated-dependencies:
- dependency-name: next
  dependency-version: 15.4.8
  dependency-type: direct:production
...

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

package.json

@@ -35,7 +35,7 @@
     "ioredis": "^5.4.1",
     "lucia": "^3.1.1",
     "lucide-react": "^0.488.0",
-    "next": "^15.3.0",
+    "next": "^15.4.8",
     "next-themes": "^0.4.4",
     "openai": "^4.77.0",
     "react": "^19.0.0-rc.1",