fix(tasks): fix task cancellation process tree leak, emit cancelled events, and refine status badges styling

internal/services/system_ws_service.go

@@ -100,6 +100,7 @@ func (m *SystemWSManager) SubscribeEvents(bus *eventbus.EventBus) {
 		constant.EventTaskTimeout,
 		constant.EventTaskRunning,
 		constant.EventTaskQueued,
+		constant.EventTaskCancelled,
 	}
 
 	for _, evt := range taskEvents {

internal/services/tasks/executor_service.go

@@ -304,6 +304,8 @@ func (h *ServerSchedulerHandler) OnTaskCompleted(req *executor.ExecutionRequest,
 			eventType = constant.EventTaskFailed
 		case constant.TaskStatusTimeout:
 			eventType = constant.EventTaskTimeout
+		case constant.TaskStatusCancelled:
+			eventType = constant.EventTaskCancelled
 		}
 		if eventType != "" {
 			eventbus.DefaultBus.Publish(eventbus.Event{