fix: package.json & yarn.lock to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-NEXT-15104645

Author: snyk-bot

package.json

@@ -27,7 +27,7 @@
     "file-saver": "^2.0.5",
     "js-yaml": "^4.1.0",
     "jszip": "^3.7.1",
-    "next": "^12.0.2",
+    "next": "^15.5.10",
     "next-compose-plugins": "^2.2.1",
     "next-images": "^1.8.1",
     "next-pwa": "^5.2.21",