fix(deps): update dependency next to v15.5.6 (#395)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

package.json

@@ -22,7 +22,7 @@
     "fumadocs-typescript": "^4.0.4",
     "fumadocs-ui": "^15.7.11",
     "lucide-react": "^0.546.0",
-    "next": "15.5.4",
+    "next": "15.5.6",
     "prettier": "^3.6.2",
     "react": "19.2.0",
     "react-dom": "19.2.0",