docs(spec): add Ubuntu Docker deployment design
Production deployment of Cyclone on a single Ubuntu Linux server:
- Two-container Docker Compose (backend + nginx frontend)
- App-layer auth: username/password, argon2id, session cookies
- 3 fixed roles: admin / operator / viewer with documented action matrix
- SQLCipher encryption at rest, key as Docker secret
- Existing BackupService autostarts (24h interval, 14-day retention)
- LAN-only bind, single operator, VPN for outside access
- Manual update via 'docker compose pull', env-var rollback
- SFTP stays stub (download ZIP + MFT UI); listed as v2
Builds on the parent 2026-06-19 production-readiness spec which
shipped local-only in-memory store + react-query wiring.
cyclone
35298907bc