fix(deps): update nextjs monorepo to v15.5.6

Author: renovate[bot]

package.json

@@ -20,7 +20,7 @@
     "@tanstack/react-query": "^4.29.12",
     "@vercel/og": "0.8.5",
     "dayjs": "1.11.19",
-    "next": "15.4.7",
+    "next": "15.5.6",
     "next-pwa": "5.6.0",
     "react": "19.0.0",
     "react-dom": "19.0.0",
@@ -52,7 +52,7 @@
     "autoprefixer": "10.4.22",
     "babel-loader": "10.0.0",
     "eslint": "9.39.1",
-    "eslint-config-next": "15.2.4",
+    "eslint-config-next": "15.5.6",
     "eslint-config-prettier": "10.1.8",
     "eslint-import-resolver-typescript": "^4.0.0",
     "eslint-plugin-import": "^2.28.1",