Security audit

Review the code/change against the common vulnerability classes and report real, evidenced findings. Confidence-calibrated: don't surface what you can't point to.

bento-ship calls this audit conditionally before final checks. Return the scope, findings and recommended fixes to the caller; the audit itself edits nothing. Ship triages local fixes and carries product/public-contract decisions into its existing decision stop.

Repo layer first. Read the repo's AGENTS.md/CLAUDE.md and, if it exists, the overlay .agents/bento/bento-cso.md at the repo root; follow it under the overlay rules.

Steps (paste as todos)