feat: Add native topology-aware deletion priority support

Implements native topology awareness in GameServer Controller.
- Adds logic to SyncPodToGs to query pods on the same node
- Calculates priority based on pod density
- Enabled via annotation 'game.kruise.io/topology-aware-deletion'

Fixes #198

Author: Nakshatra Sharma

pkg/controllers/gameserver/gameserver_manager.go

@@ -301,6 +301,35 @@ func (manager GameServerManager) SyncPodToGs(ctx context.Context, gss *gameKruis
 	// sync Service Qualities
 	sqConditions := syncServiceQualities(gss.Spec.ServiceQualities, pod.Status.Conditions, gs, manager.eventRecorder)
 
+	// Topology-aware Deletion Priority (Native Support)
+	if val, ok := gs.GetAnnotations()["game.kruise.io/topology-aware-deletion"]; ok && val == "true" && pod.Spec.NodeName != "" {
+		podList := &corev1.PodList{}
+		opts := []client.ListOption{
+			client.InNamespace(pod.Namespace),
+			client.MatchingFields{"spec.nodeName": pod.Spec.NodeName},
+		}
+		if err := manager.client.List(ctx, podList, opts...); err == nil {
+			podCount := len(podList.Items)
+			ownerMap := make(map[types.UID]bool)
+			for _, p := range podList.Items {
+				for _, owner := range p.OwnerReferences {
+					ownerMap[owner.UID] = true
+				}
+			}
+			// Priority = 100 - (pods * 10) - (owners * 5)
+			priority := 100 - (podCount * 10) - (len(ownerMap) * 5)
+			if priority < 0 {
+				priority = 0
+			}
+			priorityStr := strconv.Itoa(priority)
+			if podDeletePriority.String() != priorityStr {
+				podDeletePriority = intstr.FromString(priorityStr)
+			}
+
+		}
+	}
+
+
 	// sync Metadata from Gss
 	if isNeedToSyncMetadata(gss, gs) {
 		gsMetadata := syncMetadataFromGss(gss)