Add sponsor regulatory attestation guard

[jaxassistant55]

@algora-pbc /claim #18

Summary

• adds a dependency-free sponsor regulatory attestation packet guard for SCIBASE issue Scientific Bounty System #18
• evaluates synthetic challenge sponsor packets for legal entity identity, authorized signer evidence, source-of-funds attestation freshness, third-party funding disclosures, sanctions/restricted-party screening, beneficial-owner screening resolution, high-value tax reporting readiness, cross-border withholding review, export-control classification, regulated-domain review, immutable public rules digest, cancellation/refund language, and compliance contact readiness
• emits challenge-level ready/hold/block decisions plus deterministic findings, packet digests, JSON/Markdown/SVG/MP4 reviewer artifacts, and an audit digest

Scope

This is a distinct Scientific Bounty System slice focused only on sponsor-side legal and regulatory attestation before a challenge opens. It avoids existing #18 work around intake, rubrics, submission workspaces, evidence freezes, arbitration, payout routing, team split ledgers, escrow readiness, payout eligibility, duplicate solver detection, sponsor scorecards, review integrity, appeals, deadline fairness, benchmark leakage, data-use agreements, human-subjects compliance, award transparency, and closeout retention.

Synthetic data only; no live sanctions, tax, payment, escrow, KYC, identity, sponsor-system calls, private sponsor data, credentials, bank details, taxpayer identifiers, regulated research records, or real sanctions records.

Validation

• npm run check
• npm test
• npm run demo
• git diff --check
• git diff --cached --check
• ffprobe -v error -select_streams v:0 -show_entries stream=codec_name,width,height,duration -of default=noprint_wrappers=1 sponsor-regulatory-attestation-packet-guard/reports/demo.mp4

Demo MP4 verification: H.264, 1280x720, 6.0 seconds.

AI-assisted with OpenAI Codex; I reviewed and verified the implementation and generated artifacts before submission. Attempt registration: #18 (comment)