Two critical fixes to prevent test timeouts:
1. Nil map panic in TestPollPVEInstanceUsesRRDMemUsedFallback:
- Test monitor was missing nodeLastOnline map initialization
- Panic occurred when pollPVEInstance tried to update nodeLastOnline[nodeID]
- Caused deadlock when panic recovery tried to acquire already-held mutex
- Added nodeLastOnline: make(map[string]time.Time) to test monitor
2. Alert manager goroutine leak in Docker tests:
- newTestMonitor() created alert manager but never stopped it
- Background goroutines (escalationChecker, periodicSaveAlerts) kept running
- Added t.Cleanup(func() { m.alertManager.Stop() }) to test helper
These fixes resolve the 10+ minute test timeouts in CI workflows.
Related to workflow run 19281508603.