[Maintenance][Alerts] Post-window verification: alert (and ticket) when a device that was online before a maintenance window is still offline after it

[ToddHebebrand]

Description

Split from #4981 (mega-issue), and the maintenance-window half of #4330. After a scheduled reboot or maintenance window, nothing in Breeze checks that the device came back:

Alert if a server that was previously online is offline at the end of that maintenance window.

When the job runs it creates a ticket to say the server is rebooting, then monitors and waits for the RMM to show it online again. If online it closes the ticket; if offline for more than 20 min it sends an urgent alert via Teams.

Today maintenanceRebootWorker.ts only issues reboots to online devices with a pending-reboot flag during an active window; there is no window-close hook, no "was online before / still offline after" comparison, and no post-maintenance alert or ticket. The generic offline alert (alertConditions/handlers/offline.ts) is typically suppressed during the window, so a server that never returns is silent until someone notices.

Proposed Fix

1. Snapshot at window open: record which targeted devices were online when the window (or reboot batch) started.
2. Verify at window close (+ grace): for each device that was online at open and has not heartbeated by windowEnd + graceMinutes (default 20), raise a maintenance_reboot_failed alert at high/critical severity through the normal alert pipeline (so Teams/email/webhook routing and escalation apply, and automations can trigger on it).
3. Optional ticket lifecycle: when a ticket target is configured, open a "Scheduled reboot in progress" ticket at batch start and auto-close it when the device is back; leave it open and escalate if verification fails. (Depends on [Alerts][Ticketing] Ticket as an alert target: 'ticket' notification channel type and 'create_ticket' automation action #5238, ticket as an alert/automation target.)

Affected Files

• apps/api/src/jobs/maintenanceRebootWorker.ts
• apps/api/src/services/alertConditions/ (new handler) or a dedicated post-maintenance job
• apps/api/src/db/schema/configurationPolicies.ts (grace + verification flags on configPolicyMaintenanceSettings)
• apps/web/src/components/configurationPolicies/featureTabs/MaintenanceTab.tsx

Reported By

stressedout9064 on Discord (#feature-suggestions, 2026-09-04 and 2026-08-30) — split from #4981; overlaps #4330 (reboot-and-monitor script). Related: #5235 (window ordering/dependency).