Poll Zabbix for toner levels on a schedule and email/webhook on a downward
crossing. Warning fires at or below the warning threshold (default 5%),
critical at the critical threshold (default 0%); both thresholds are settings.
State lives in printersupplyalerts so an alert fires once per crossing and
re-arms after a refill.
Recipients mirror the printedparts pattern: plugin-scoped shopdb users +
roles + free-text emails (falling back to the site alert_recipients), and a
chosen support team's webhook (falling back to the site alert_webhook_url).
- PrinterSupplyAlert model + migration printers0002supplyalerts
- alerttier(remaining, warning, critical) + check_supplies poller
- flask printers check-toner-alerts CLI (run via scheduled task/cron)
- printers alert settings + Low-Toner Alerts settings page
- 7 tests: tier boundaries, once-per-crossing + re-arm, toner-only scope,
custom thresholds, support-team webhook routing