fix: upgrade Next.js to 15.5.7 to patch CVE-2025-66478

Critical (CVSS 10.0) Remote Code Execution vulnerability in React Server Components.
Affects Next.js 15.x < 15.5.7.

Reference: https://nextjs.org/blog/CVE-2025-66478

Author: dcbouius

package-lock.json

@@ -12,7 +12,7 @@
     "@types/react": "^18.2.0",
     "@types/react-dom": "^18.2.0",
     "@vectorize-io/vectorize-connect": "^0.4.0",
-    "next": "15.5.3",
+    "next": "^15.5.7",
     "react": "^18.2.0",
     "react-dom": "^18.2.0"
   },