demos: add 4 task sample videos (wo-triangle, wo-grid-3x3, cv-drag-slider, cv-connect-dots)

leaderboard: drop pilot-claude row; closed/frontier models off-board (open-weight evals only)

results: pilot-claude 95% (headless/nested)

results: pilot-claude 95% (headless/nested)

results: pilot-claude 100% (headless/nested)

leaderboard: video samples section + LFS for mp4 + graceful-hide

pilot row: proper model slug claude-fable-5

emoji within HF pattern

leaderboard: wisp-styled static board, pilot-claude first row

initial commit