feat(tasks): implement atomic claims and leases

backend-api/internal/transport/webui/usecase_adapter.go

@@ -128,9 +128,9 @@ func actorUserID(ctx context.Context) string {
 	return principal.UserID
 }
 
-func (adapter *UsecaseAdapter) CancelPending(
+func (adapter *UsecaseAdapter) CancelTask(
 	ctx context.Context,
-	input CancelPendingInput,
+	input CancelTaskInput,
 ) (Task, error) {
 	task, err := adapter.tasks.Cancel(ctx, usecase.CancelTaskCommand{
 		CreatorSubject: localAdminSubject,