Serve the read verbs on the serving controller's own connection, and name every connection

Each verb ran as a process that dialled the bus, so hundreds of short
connections an hour, all named mesh-controller, hid any client reconnecting
in a loop (hq issue 327). D15 now says a user whose connections keep dropping.

cmd/mesh-controller/queue.go

@@ -6,6 +6,7 @@ import (
 	"errors"
 	"flag"
 	"fmt"
+	"io"
 	"os"
 	"sort"
 	"strings"
@@ -37,21 +38,19 @@ const (
 	killAnswer = 75 * time.Second
 )
 
-// dialTheBus opens the controller's own connection, for a command that reads or changes the queue.
+// dialTheBus is the controller's connection, for a command that reads or changes the queue: the serving
+// controller's own, lent, when this process is it (novox/hq issue 327).
 func dialTheBus() (*broker.JetStream, error) {
-	address, err := broker.BusAddress()
-	if err != nil {
-		return nil, err
-	}
-	js, err := broker.Dial(address)
-	if err != nil {
-		return nil, fmt.Errorf("cannot reach the bus: %w", err)
-	}
-	return js, nil
+	return aBus()
 }
 
 // queueCommand prints every ask in the build seat's work queue.
 func queueCommand(ctx context.Context, args []string) error {
+	return listQueue(ctx, args, os.Stdout)
+}
+
+// listQueue is `queue`: the build queue, as a person reads it or as JSON.
+func listQueue(ctx context.Context, args []string, w io.Writer) error {
 	set := flag.NewFlagSet("queue", flag.ContinueOnError)
 	asJSON := set.Bool("json", false, "the queue as JSON")
 	if _, err := parseAround(set, args); err != nil {
@@ -72,10 +71,10 @@ func queueCommand(ctx context.Context, args []string) error {
 		if err != nil {
 			return err
 		}
-		fmt.Println(string(body))
+		fmt.Fprintln(w, string(body))
 		return nil
 	}
-	fmt.Print(queueText(q, time.Now()))
+	fmt.Fprint(w, queueText(q, time.Now()))
 	return nil
 }