Add revenue commitment true-up guard

[xiefuzheng713-alt]

/claim #20

Summary

• Add a dependency-free revenue-commitment-trueup-guard module for the Revenue Infrastructure bounty.
• Validate enterprise minimum-commitment true-up release readiness across metered usage drawdown, proposed true-up variance, duplicate true-up windows, amendment effective dates, overage evidence, and SLA credit evidence/caps.
• Emit deterministic RELEASE_INVOICE, REVIEW_BEFORE_RELEASE, or HOLD_INVOICE actions from synthetic fixtures only.

Reviewer Artifacts

• Demo JSON: revenue-commitment-trueup-guard/artifacts/demo-output.json
• Markdown report: revenue-commitment-trueup-guard/artifacts/reviewer-report.md
• Risk map SVG: revenue-commitment-trueup-guard/artifacts/trueup-risk-map.svg
• Demo video: revenue-commitment-trueup-guard/artifacts/commitment-trueup-guard-demo.mp4

Verification

• node revenue-commitment-trueup-guard/test.js
• node revenue-commitment-trueup-guard/demo.js
• git diff --check
• Demo MP4 read check: ffmpeg -v error -i revenue-commitment-trueup-guard/artifacts/commitment-trueup-guard-demo.mp4 -f null -

Safety

• Synthetic fixtures only.
• No credentials, real customers, private billing data, payment processors, external APIs, wallets, or payout systems.