build(deps): bump next from 15.4.8 to 15.4.9 in /playground/frontend (#1035)

Bumps [next](https://github.com/vercel/next.js) from 15.4.8 to 15.4.9.
- [Release notes](https://github.com/vercel/next.js/releases)
- [Changelog](https://github.com/vercel/next.js/blob/canary/release.js)
- [Commits](vercel/next.js@v15.4.8...v15.4.9)

---
updated-dependencies:
- dependency-name: next
  dependency-version: 15.4.9
  dependency-type: direct:production
...

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

Author: dependabot[bot]

playground/frontend/package.json

@@ -15,7 +15,7 @@
 		"@tiptap/react": "^3.0.1",
 		"@tiptap/starter-kit": "^3.0.1",
 		"jwt-encode": "^1.0.1",
-		"next": "15.4.8",
+		"next": "15.4.9",
 		"react": "^19.0.0",
 		"react-dom": "^19.0.0"
 	},