MVS4 — Production Deployment & Access Controls

What's new

• Deployed to Fly.io with Neon managed PostgreSQL, HTTPS, and secrets management
• RBAC on routes for initial release (admin-only access to chat APIs)
• Usage limits enforced for non-admin users
• AI provider adapter with prompt caching (threadId-based)
• UI improvements: safety banner, disclaimer, Open Graph image, mobile-responsive layout
• Automated CD via GitHub Actions for production deployment