Key decisions:
- Docker for MCP server (isolation)
- One Ed25519 key, claude_executor user on all servers
- UFW: allow 22, 9090; deny all else
- fail2ban + Cloudflare Access for security
- Approval logic stays in Arbiter
- docker-compose + systemd for startup
- Uptime Kuma for monitoring (CPU temp, disk I/O)
- HandleLidSwitch=ignore for shelf mode
Chronicler #73