MP-8506 Create buzz.xyz Droplet 1-Click

[v-pjalandra-do]

Summary

• JIRA — MP-8506
• Add a new Buzz (buzz.xyz) Droplet 1-Click on Ubuntu 24.04 under buzz-24-04/
• Deploy the official Docker Compose stack (relay + Postgres + Redis + MinIO) with host Caddy shortlived TLS; bind the relay to localhost and expose only 80/443
• Generate per-droplet secrets and owner keypair on first boot; run the relay in closed membership mode
• Include MOTD, systemd unit, start/stop/restart/status/update helpers, and a domain setup helper backed by a shipped Caddyfile.domain.tmp

Test plan

• Create a Droplet from the snapshot; confirm SSH unlocks after 001_onboot
• Open https://<droplet-ip>; import owner secret key from /root/buzz_credentials.txt
• Confirm port 3000 is not public; only 22/80/443 via UFW
• Exercise /opt/start-buzz.sh, /opt/stop-buzz.sh, /opt/restart-buzz.sh, /opt/status-buzz.sh
• Buzz Desktop: import owner nsec1 from /root/buzz_credentials.txt, join wss://<droplet-ip>, send a message in a channel
• Non-member identity is denied; after /opt/buzz/run.sh add-member <npub-or-hex>, that identity can join; verify with list-members (and optional remove-member)