fix(web/admin): expose PoisonQueueBacklog event types in OpsAlertRules UI

The previous commit added the two new EventTypes server-side
(PoisonQueueBacklogHigh / PoisonQueueBacklogCritical) but the admin alert
rules section hardcodes its known-event-types catalog in the component
itself - so the dropdown didn't list them and operators couldn't wire
Telegram to the new alerts.

Adds both strings to the Security category, matching how the SignalR/Cert
event types were registered when those watchers landed.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/Web/autopilot-monitor-web/app/admin/components/OpsAlertRulesSection.tsx

@@ -19,6 +19,8 @@ const OPS_EVENT_TYPES: Record<string, string[]> = {
     "SignalRConnectionsCritical",
     "SignalRMessagesHigh",
     "SignalRMessagesCritical",
+    "PoisonQueueBacklogHigh",
+    "PoisonQueueBacklogCritical",
   ],
   Tenant: ["TenantOffboarded"],
   Agent: ["BlobStorageMissing", "BlobStorageUnreachable", "NewImeVersionDetected", "ExcessiveSessionEvents"],