Add legal review accessible UI surface

[nonggde]

Closes #616

Summary

• add a folder-local Legal and Compliance Review Flag UI surface with loading, error, empty, and success states
• add queue/detail review components with native keyboard controls, labels, live regions, and visible focus states
• add synthetic UI review fixtures plus accessibility and visual style docs
• add a zero-dependency Node contract test for state coverage, ARIA/focus requirements, and docs

Scope

• only touches tools/v2/team/legal-and-compliance-review-flag/
• no app shell, dashboard, routing, auth, wallet, Stellar, database, inbox, mail rendering, notification, assignment write, external provider, or design-system integration
• no production data, live network calls, persistence, secrets, or side effects

Validation

• node --test tools/v2/team/legal-and-compliance-review-flag/tests/ui-accessibility-contract.test.mjs
• npx --yes prettier --check on the changed Legal and Compliance Review Flag UI files
• git diff --check
• ASCII scan over tools/v2/team/legal-and-compliance-review-flag