chore(deps): add defu

Author: sushichan044

packages/eslint-config/package.json

@@ -42,6 +42,7 @@
     "@typescript-eslint/utils": "8.35.0",
     "astro-eslint-parser": "1.2.2",
     "astrojs-compiler-sync": "1.1.1",
+    "defu": "6.1.4",
     "eslint-config-flat-gitignore": "2.1.0",
     "eslint-config-prettier": "10.1.5",
     "eslint-plugin-astro": "1.3.1",