feat(syslog): set-up help on the page, port 5514 published, Docker-hidden senders called out (#6003)

The Syslog page says where to send (this server, its port and protocols) and
where the setting is on Synology, QNAP, TrueNAS, OpenWrt, UniFi and rsyslog,
open until a device sends. A sender whose address is on Steward's own
container network (Swarm ingress publishing hides the real sender) is
flagged, with the host-mode ports to publish instead. compose files and the
Dockerfile publish 5514/udp and /tcp; docs/plugins/syslog.md describes the
plugin and the deploy.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docker-compose.yml

@@ -8,6 +8,8 @@ services:
     command: ["steward", "--host", "0.0.0.0", "--port", "5000", "--debug"]
     ports:
       - "5000:5000"
+      - "5514:5514/udp"     # syslog (plugins/syslog)
+      - "5514:5514/tcp"
     volumes:
       - app_data:/data
       # Live-edit core + first-party plugins without rebuilding. PYTHONPATH=/app