Add review civility evidence gate

[sravan27]

@algora-pbc /claim #15

Summary

• add a focused peer-review civility and evidence gate for the Community & User Reputation System
• hold harassment, protected-identity disclosure, anonymous reviewer leaks, and unsupported reputation-damaging low scores before profile or timeline impact
• generate deterministic JSON/Markdown/SVG/PNG/MP4 moderation proof artifacts from synthetic data

Validation

• node review-civility-evidence-gate/test.js
• node review-civility-evidence-gate/demo.js
• node --check review-civility-evidence-gate/index.js
• node --check review-civility-evidence-gate/sample-data.js
• node --check review-civility-evidence-gate/test.js
• node --check review-civility-evidence-gate/demo.js
• git diff --check
• ffprobe confirms review-civility-evidence-gate/reports/demo.mp4 is H.264 1280x720, 12 seconds

Notes

• dependency-free core logic
• synthetic data only; no credentials or external services
• distinct from broad reputation ledgers, endorsement-ring guards, review timeliness, badge renewal, leaderboard eligibility, anonymous leak-only, COI assignment, and appeals modules