Document published animation custody

[ReidSurmeier]

Summary

• classify the repository as a Published Media Snapshot with no runtime or deployment ownership
• preserve the three MP4 exports through exact size and SHA-256 contract tests
• document missing generating source and publication-rights boundaries
• add project, domain, ADR, agent, triage, and CI contracts

TDD evidence

• Red: the new repository-contract suite failed because the documentation contract did not exist; the issue-link assertion later failed until GitHub follow-ups were recorded.
• Green: python3 -m unittest discover -s tests -v passes 5 tests.
• Refactor/validation: compileall, diff check, staged Gitleaks, and gitnexus analyze --index-only . pass.

Closes no follow-up issues: #1, #2, and #3 intentionally remain open.