Add reproducibility badge verification gate

[zergzorg]

Summary

• Adds a self-contained reproducibility-badge-verification-gate/ module for SCIBASE issue Community & User Reputation System #15.
• Verifies primary reproducibility badge issuance from independent reproduction evidence: artifact checksums, environment digests, output matches, test results, run-log checksums, disclosures, and author/collaborator conflicts.
• Produces deterministic bronze/silver/gold, revise, or hold decisions with reviewer actions and generated JSON, Markdown, SVG, and MP4 artifacts from synthetic data only.

Non-overlap

This slice focuses on first-time reproducibility badge verification. It intentionally avoids duplicating existing issue #15 work on broad reputation ledgers, appeal guardrails, review calibration, COI assignment, endorsement rings, badge renewal, leaderboards, civility checks, timeliness credits, mentorship ladders, anonymous identity checks, and transparency receipts.

Validation

• npm --prefix reproducibility-badge-verification-gate run check
• npm --prefix reproducibility-badge-verification-gate test
• npm --prefix reproducibility-badge-verification-gate run demo
• ffprobe -v error -show_entries format=duration,size -show_entries stream=codec_name,width,height -of default=noprint_wrappers=1 reproducibility-badge-verification-gate/reports/demo.mp4
• git diff --check

Demo video: reproducibility-badge-verification-gate/reports/demo.mp4

AI-assisted with OpenAI Codex; reviewed and validated locally before submission.

/claim #15