Add layperson summary safety guard

[attaboy11]

/claim #13

Summary

• Adds a self-contained lay-summary-safety-guard/ module for the AI-Assisted Research Tools MVP bounty.
• Audits generated layperson explanations before public sharing by checking source-evidence overlap, unsupported benefit claims, causal overstatement, medical-advice wording, missing uncertainty, missing limitations, unexplained jargon, and reading-level drift.
• Generates deterministic JSON, Markdown, SVG, and MP4 reviewer artifacts using synthetic data only and no external services.

Scope distinction

This is focused specifically on public-facing layperson summaries from the AI paper summarizer. It is separate from existing broad AI tool suites, evidence-grounded summarizers, citation metadata/context/style/diversity/retraction slices, manuscript similarity, methods reproducibility, reporting-guideline, unit consistency, biomethods provenance, statistical power, multiple-comparison, certainty/tone, and ethics/data-availability work.

Validation

• node lay-summary-safety-guard/test.js
• node lay-summary-safety-guard/demo.js
• node lay-summary-safety-guard/render-video.js
• node --check lay-summary-safety-guard/index.js
• node --check lay-summary-safety-guard/sample-data.js
• node --check lay-summary-safety-guard/test.js
• node --check lay-summary-safety-guard/demo.js
• node --check lay-summary-safety-guard/render-video.js
• git diff --check
• ffprobe -v error -select_streams v:0 -show_entries stream=pix_fmt,width,height -show_entries format=duration,size -of default=nw=1 lay-summary-safety-guard/reports/demo.mp4

MP4 check result: width=960, height=540, pix_fmt=yuv420p, duration=4.000000, size=23817.