Add collaborative cover-letter export guard

[drsteinerdj]

/claim #12

Summary

Adds a self-contained collab-cover-letter-export-guard/ reviewer artifact for the real-time collaborative research editor bounty. This slice focuses on the journal cover-letter and submission-facing correspondence packet before manuscript export.

It validates synthetic collaborative submission packets for:

• stale manuscript/cover-letter hashes after final edits
• missing or stale corresponding-author approval
• coauthor approval drift after the final manuscript version
• novelty, ethics, data availability, and conflict statement mismatches between manuscript and cover letter
• private reviewer/collaborator notes leaking into editor-facing correspondence

The module emits deterministic RELEASE, REVIEW, or HOLD decisions with JSON, Markdown, SVG, and MP4 reviewer artifacts.

Non-overlap

This is intentionally separate from the existing issue #12 slices for broad editor foundations, operation replay, notebook queues, reference formatting/merge, equation and figure anchors, data-availability statements, journal-style section order, footnotes, supplementary-material exports, statistics reporting, accessibility, clipboard/import provenance, and terminology/unit consistency.

Validation

Run from collab-cover-letter-export-guard/:

npm run check
npm test
npm run demo
npm run demo:video

Also verified:

git diff --check
ffprobe -v error -select_streams v:0 -show_entries stream=codec_name,width,height,r_frame_rate -show_entries format=duration,size -of default=noprint_wrappers=1 collab-cover-letter-export-guard/reports/demo.mp4

MP4 demo artifact:

• H.264
• 960x540
• 12 fps
• 4.0 seconds

No credentials, private manuscripts, external APIs, or live editor services are used.