feat: expand AI moderation with structured analysis, review workflow, and guardrails
- Add structured AI moderation fields (categories, severity, confidence,
recommended_action, policy_version, evidence) to messages table
- Add moderation_reviews, moderation_actions, and retention_policies tables
- Upgrade LLM response parsing to support structured metadata with backwards
compatibility for legacy responses
- Implement public AI evaluation review UI with decision controls
(approve, false positive + reanalyze, escalate)
- Add auto-delete guardrails requiring high confidence, severity, and
allowed categories; log all attempts to moderation_actions
- Add retention manager scaffolding for messages/attachments/voice
- Add action executor for moderation actions (mute, warn, kick, ban)
- Add review routes: GET/POST/PATCH /api/reviews, GET/POST/PATCH /api/actions
- Preserve auth separation: voice/media/recordings gated, review public
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
