fix: keep eslint at ^9.39.4 pending eslint-plugin-github v10 support

eslint-plugin-github@6.0.0 peers eslint@"^8 || ^9" and no release supports
eslint 10 yet (upstream: github/eslint-plugin-github#686). Revert eslint and
@eslint/js to 9.x while keeping the other 4 bumps in this group, regenerate
package-lock.json.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: platinummonkey