[ofeq-dev]

Summary

Three fixes surfaced by a first-run impression of the README + live demo:

1. README: validity-rule column rendered blank. The rule cells contained literal | characters (|dist(a,b) − dist(a,c)| < EPS), which CommonMark parses as column separators, collapsing the column. Escaped as \|.
2. Live-demo videos did not load. Two stacked causes:
   • pages.yml checked out without lfs: true, so the deploy staged ~130-byte LFS pointer files instead of the real MP4s. Added lfs: true.
   • Even with real files, the committed videos are mp4v (MPEG-4 Part 2, ADR 0004) — Chrome/Firefox/Edge do not play MPEG-4 Part 2 in <video> (verified via ffprobe: codec_name=mpeg4). The deploy job now re-encodes the site copies to H.264 (ffmpeg -c:v libx264 -pix_fmt yuv420p -movflags +faststart); assets/videos/*.mp4 stays mp4v — the pipeline deliverable is unchanged.
3. README sample output was inaccurate — omitted the two row 3 / row 4 error lines a real run prints (those rows are deliberately invalid by design). Output block now matches an actual run.

Also: site quickstart said "Python ≥ 3.10"; numpy 2.5 requires ≥ 3.12 (README already said this) — aligned.

Verification

• 123 tests pass locally on the pre-fix tree (deliverable untouched except README wording — no code change; CI will confirm).
• Re-encode verified locally: output plays as H.264 (codec_name=h264), error-free with -v error.

AI disclosure

This PR was authored by an AI assistant (OpenCode agent, GLM) based on a user's issue report; all changes reviewed against ADR 0004 and the testing strategy.