work-on-issue

Use when the user says "work on issue", "implement issue", "/work-on-issue", or asks to implement a GitHub issue end-to-end (not merely validate it). Takes an issue URL or number (defaults to the just-validated issue). Implements the fix in an isolated worktree, verifies it, commits and pushes, and opens a PR that closes the issue. Default follow-on when validate-issue offers "work on issue".