Fix CI: downgrade eslint to ^8.57.1 for eslint-plugin-github compatibility

Author: Copilot

package.json

@@ -30,7 +30,7 @@
     "@github/prettier-config": "0.0.4",
     "@types/node": "^22.13.10",
     "chai": "^4.3.4",
-    "eslint": "^10.5.0",
+    "eslint": "^8.57.1",
     "eslint-plugin-github": "^4.2.0",
     "karma": "^6.3.4",
     "karma-chai": "^0.1.0",