Agent Skills: auto-review-plan

Automatically iterate review-plan against a plan until no safe blocking edits remain. Use when user wants to "auto-review-plan", "auto-fix the plan", tighten a plan without staying in the loop for each finding, or harden an `IMPLEMENTATION_PLAN_*.md` / `REFACTOR_PLAN_*.md` / plan-mode draft before implementation. Auto-applies small, concrete blocking edits; batches structural recommendations for a single end-of-run approval pass.