Add repository access review gate

[tuanadr]

/claim #10

Summary

• Adds a self-contained repository access review gate for release/export readiness.
• Flags stale external reviewers, expired restricted-data approval, privileged role drift, secret-link exposure, and license/access mismatch.
• Emits a deterministic release hold packet with access matrix, reviewer checklist, audit digest, SVG/Markdown/JSON outputs, and a short MP4 demo.

Demo artifacts

• repository-access-review-gate/demo-output/release-hold-packet.json
• repository-access-review-gate/demo-output/reviewer-packet.md
• repository-access-review-gate/demo-output/demo.svg
• repository-access-review-gate/demo-output/demo.mp4

Validation

• node repository-access-review-gate/test.js
• node repository-access-review-gate/demo.js
• node --check repository-access-review-gate/index.js
• node --check repository-access-review-gate/test.js
• node --check repository-access-review-gate/demo.js
• node --check repository-access-review-gate/sample-data.js
• ffprobe -v error -show_entries format=duration,size -show_entries stream=codec_name,width,height -of default=noprint_wrappers=1 repository-access-review-gate/demo-output/demo.mp4
• git diff --check
• git diff --cached --check