Add challenge communication parity guard

[Jorel97]

@algora-pbc /claim #18
/claim #18

Summary

• Add a self-contained challenge-communication-parity-guard/ module for the Scientific Bounty System.
• Detect material sponsor communications that are not delivered equally to all eligible solver teams.
• Flag hidden/private hints, stale rule digests, channel coverage gaps, inaccessible required attachments, unfair acknowledgement windows, and missing acknowledgement evidence.
• Emit deterministic release, revise, or hold decisions with remediation steps and reviewer artifacts.

Demo video

• challenge-communication-parity-guard/reports/demo.mp4
• challenge-communication-parity-guard/reports/demo.gif

Validation

• npm test
• npm run demo
• npm run demo:video
• git diff --check

Notes

Synthetic data only. No credentials, private challenge records, payment systems, external APIs, or live platform calls are used.