Add Zabbix template with offline and last-seen triggers

- zabbix_template.yaml: importable template "Yodmon Yodeck Player"
  - 5 SNMP items using {$YODECK_ID} host macro for per-host OIDs
  - Trigger: offline warning after 30 minutes (yodeck.online < 1)
  - Trigger: last seen > 4 hours (now() - yodeck.last_seen_ts > 14400)
- snmp/pass_persist.py: add col 7 — last_seen as Unix timestamp
- app/zabbix.py: link hosts to template, upsert {$YODECK_ID} macro;
  existing hosts get template linked on next sync automatically
- app/config.py: add ZABBIX_TEMPLATE setting

Import zabbix_template.yaml once via Zabbix UI, then redeploy.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docker-compose.yml

@@ -36,6 +36,7 @@ services:
       ZABBIX_USER: ""
       ZABBIX_PASSWORD: ""
       ZABBIX_HOST_GROUP: "Yodeck Players"
+      ZABBIX_TEMPLATE: "Yodmon Yodeck Player"
       ZABBIX_SNMP_COMMUNITY: "public"
 
 volumes: