Compare agent skills before installing.

Use when the user wants a GitHub issue planned by Fable 5.1 and then implemented in one shot, without validation or a review loop — "fableplan-work-on-issue", "fableplan and work on #N", "plan #N with fable then implement it". Runs the fableplan planning phase (Fable 5.1 produces and posts an implementation plan to the issue), then hands off to work-on-issue, which implements the plan in an isolated worktree and opens a PR that closes the issue. Stops at the open PR — it does not request review or loop. The trimmed counterpart to validate-fableplan-loop (no validate-issue step, no @claude review cycle).

Implement work from an approved spec or ticket set, run focused and full tests, invoke code review, and commit the result to the current branch.