- New `SIMPLELOGIN_TS_HOSTNAME` config variable (default: simplelogin)
- `smtp` entryPoint on :25 in traefik.yml static config
- Port 25 binding added to docker-compose.yml traefik service
- New conf.d/simplelogin-smtp.yml TCP router → SimpleLogin host via Tailscale
- Independent idempotent UFW rule for 25/tcp (self-heals on existing hosts)