The controller no longer subscribes to the alive message: HostBeats, its handler, the heartbeat-gap duration and a fixed silent bound (issue 1183, AC3, AC4, AC5)

internal/link/receive_nats.go

@@ -114,12 +114,8 @@ func (n *natsInbound) Receive(ctx context.Context, act func(context.Context, Con
 	// Heartbeats, on core NATS and off any stream (design 25 §3). Their own subscription because
 	// they are their own guarantee: a lost one is the next one.
 	beats := make(chan *nats.Msg, Prefetch)
-	alive, err := conn.ChanSubscribe(AliveSubjects, beats)
-	if err != nil {
-		return fmt.Errorf("subscribing to heartbeats: %w", err)
-	}
-	defer func() { _ = alive.Unsubscribe() }()
-	// And each machine's node tools, on the same channel: as cheap, and lost the same way.
+	// Each machine's node tools, as cheap and lost the same way. The node-engine's alive message is not subscribed to: a
+	// machine's last word is the watchman's presence (novox/hq ADR 0433 §3, issue 1183).
 	toolsAlive, err := conn.ChanSubscribe(ToolsAliveSubjects, beats)
 	if err != nil {
 		return fmt.Errorf("subscribing to the node tools' heartbeats: %w", err)
@@ -283,8 +279,6 @@ func kindOfSubject(subject string) (string, bool) {
 		switch rest {
 		case "report":
 			return KindReport, true
-		case "alive":
-			return KindHeartbeat, true
 		case "tools-alive":
 			return KindToolsHeartbeat, true
 		case "health":