packaging/server/install.sh sets up Debian/Ubuntu behind Caddy: binary from
its release archive, the source tree it sits in, the latest release or a
clone (temporary swap under 2 GB of memory), user, dirs and config only when
missing, systemd unit, Caddy site, nightly backup timer, ufw for 22/80/443;
safe to re-run for upgrades. docs/server.md gains Running a public server
(limits, expiry, moderation, operator responsibility, no end-to-end
encryption, threat model) and an install.sh walk-through; protocol, MCP,
CLI and parity docs updated.
