Gang-termination breach formula rework + E2E scenarios (GT-1 through GT-6)

.github/workflows/build-check-test.yaml

@@ -117,6 +117,8 @@ jobs:
         include:
           - test_name: gang_scheduling
             test_pattern: "^Test_GS"
+          - test_name: gang_termination
+            test_pattern: "^Test_GT"
           - test_name: rolling_updates
             test_pattern: "^Test_RU"
           - test_name: ondelete_updates
@@ -194,6 +196,7 @@ jobs:
       matrix:
         include:
           - test_name: gang_scheduling
+          - test_name: gang_termination
           - test_name: rolling_updates
           - test_name: startup_ordering
           - test_name: Topology_Aware_Scheduling

operator/api/common/constants/constants.go

@@ -120,6 +120,13 @@ const (
 	// ConditionTypePodCliqueScheduled indicates that the PodClique has been successfully scheduled.
 	// This condition is set to true when number of scheduled pods in the PodClique is greater than or equal to PodCliqueSpec.MinAvailable.
 	ConditionTypePodCliqueScheduled = "PodCliqueScheduled"
+	// ConditionTypeGangTerminationInProgress indicates that gang termination has fired for this resource and the
+	// gang termination is still in flight. The condition is set when gang termination deletes the PodCliques
+	// (either PCSG-replica scoped or PCS-level) and is cleared when MinAvailableBreached transitions back to
+	// False (workload recovered). While the condition is True, further gang-termination action is suppressed —
+	// at most one fire per breach episode, regardless of how long the workload stays below MinAvailable.
+	// Its only Reason is ConditionReasonGangTerminationActive.
+	ConditionTypeGangTerminationInProgress = "GangTerminationInProgress"
 	// ConditionTopologyLevelsUnavailable indicates that the required topology levels defined on a PodCliqueSet for topology-aware scheduling are no longer available.
 	// This can happen when the ClusterTopologyBinding resource is modified which removes one or more levels required by the PodCliqueSet.
 	ConditionTopologyLevelsUnavailable = "TopologyLevelsUnavailable"
@@ -145,6 +152,12 @@ const (
 	ConditionReasonSufficientAvailablePCSGReplicas = "SufficientAvailablePodCliqueScalingGroupReplicas"
 	// ConditionReasonUpdateInProgress indicates that the resource is undergoing rolling update.
 	ConditionReasonUpdateInProgress = "UpdateInProgress"
+	// ConditionReasonGangTerminationActive is the (only) Reason paired with
+	// ConditionTypeGangTerminationInProgress=True. The Kubernetes condition API requires a
+	// non-empty Reason, and the flag has exactly one cause, so this Reason simply restates the
+	// Type in the CamelCase token form callers branch on. If a second cause for the flag is ever
+	// introduced, add a distinct Reason then.
+	ConditionReasonGangTerminationActive = "GangTerminationActive"
 	// ConditionReasonClusterTopologyNotFound indicates that the ClusterTopologyBinding resource required for topology-aware scheduling was not found.
 	ConditionReasonClusterTopologyNotFound = "ClusterTopologyNotFound"
 	// ConditionReasonTopologyLevelsUnavailable indicates that the one or more required topology levels defined on a