Add TODO and enhanced comment about risk if vm.Properties.TimeCreated is never populated

Co-authored-by: rakechill <30397998+rakechill@users.noreply.github.com>

Author: Copilot

pkg/cloudprovider/cloudprovider.go

@@ -538,6 +538,10 @@ func (c *CloudProvider) vmInstanceToNodeClaim(ctx context.Context, vm *armcomput
 		// Fallback to current time to ensure garbage collection grace period is enforced
 		// when TimeCreated is unavailable. Without this, CreationTimestamp would be epoch (zero value)
 		// and the instance could be immediately garbage collected, bypassing the 5-minute grace period.
+		// TODO: Investigate a more fail-safe approach. If vm.Properties.TimeCreated is NEVER populated,
+		// this fallback means the VM will never be garbage collected since we call this helper every time
+		// we create an in-memory NodeClaim. We currently assume this shouldn't happen because VMs that fail
+		// to come up should eventually stop appearing in Azure API responses.
 		nodeClaim.CreationTimestamp = metav1.Time{Time: time.Now()}
 	}
 	// Set the deletionTimestamp to be the current time if the instance is currently terminating