Answer the build queue as data too, so a check can say how far back it waits

The queue verb answered only a table, so nothing outside the controller
could say an ask's place in the queue. It now asks its command for JSON:
each ask's state, kind, repository, commit, machine, since and position
among the waiting, with the table carried beside it and answered as the
verb's output, both written from one read. A repository's password, if
one were ever written into it, is left out of what is shown.

novox/hq issue 455

cmd/mesh-controller/queue_test.go

@@ -326,7 +326,7 @@ func TestTheQueueVerbsRunTheirCommands(t *testing.T) {
 		args map[string]any
 		want []string
 	}{
-		{"queue", nil, []string{"queue"}},
+		{"queue", nil, []string{"queue", "--json"}},
 		{"cancel", map[string]any{"id": "build-1"}, []string{"cancel", "build-1"}},
 		{"clear", nil, []string{"clear"}},
 		{"clear", map[string]any{"dead": "true"}, []string{"clear", "--dead"}},