issue 974: the builders say the checks they run in a bucket that ages, and a builder drops a waiting request for a head and trunk commit another is running

internal/broker/checks_test.go

@@ -26,6 +26,9 @@ func TestTheBuildAgentReadsAndWatchesThePullRequestsKeys(t *testing.T) {
 		"$JS.API.CONSUMER.MSG.NEXT.CHECKS_READY.CHECKS_READY_worker",
 		"$JS.API.CONSUMER.MSG.NEXT.CHECKS_OTHER.CHECKS_OTHER_worker",
 		"$JS.ACK.CHECKS_OTHER.CHECKS_OTHER_worker.>",
+		// And the bucket of the checks running, which it writes and reads (ADR 0406 §3).
+		"$KV." + CheckRunningBucket + ".>",
+		"$JS.API.DIRECT.GET.KV_" + CheckRunningBucket + ".>",
 	} {
 		has(t, perms.Publish, s)
 	}