fix(deps): revert eslint to ^8.0.0 to match package-lock.json

Renovate auto-merged the eslint v9 bump without regenerating
package-lock.json (which still has eslint@8.19.0). This mismatch
causes npm ci to fail across all Node versions. eslint is a dev-only
dependency so there is no runtime security impact from staying on v8.

Author: orius123

package.json

@@ -68,7 +68,7 @@
     "@types/node": "^22.0.0",
     "@typescript-eslint/eslint-plugin": "^5.25.0",
     "@typescript-eslint/parser": "^5.27.0",
-    "eslint": "^9.0.0",
+    "eslint": "^8.0.0",
     "eslint-config-airbnb-base": "^15.0.0",
     "eslint-config-airbnb-typescript": "^17.0.0",
     "eslint-config-prettier": "^10.0.0",