build(deps): bump next from 15.5.9 to 15.5.15

Bumps [next](https://github.com/vercel/next.js) from 15.5.9 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@v15.5.9...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]

package.json

@@ -31,7 +31,7 @@
     "geist": "^1.3.0",
     "input-otp": "^1.4.2",
     "lucide-react": "^0.525.0",
-    "next": "^15.5.9",
+    "next": "^15.5.15",
     "next-themes": "^0.4.4",
     "postgres": "^3.4.4",
     "radix-ui": "^1.4.3",