Take over a GitHub Dependabot security alert and remediate it, then commit and push the fix on a new branch and open a PR. Use whenever the user provides a Dependabot alert URL (github.com/<owner>/<repo>/security/dependabot/<number>) and asks to fix it, resolve it, or "handle this alert". Covers direct bumps, transitive dependencies requiring resolutions/overrides, and cases where no patched version is installable yet.
