Add a Compare tab to /topologies: pick a task + roles + topology kinds, build a graph per kind, run POST /api/topologies/compare, and render a leaderboard table + a quality/cost Pareto scatter (SVG, no deps). Wrap Build + Compare in a tabbed TopologyWorkbench. e2e p8 extended to run a comparison end-to-end (build×N → compare → leaderboard + Pareto). Full suite 39 green; build + TS clean. Co-Authored-By: Claude Opus 4.8 <[email protected]>