node-tools: keep the stopping-runtime test under a second, and start no first bundle once stopping

The test watched two seconds per row; a 10 ms restart pause and a 250 ms window
prove the same. launch.Start itself now refuses while the runtime stops, so a
reload's first start is held too (issue 1126).

node-tools/internal/launch/launch.go

@@ -194,6 +194,9 @@ var colour = regexp.MustCompile("\x1b\\[[0-9;]*m")
 // Start launches one bundle and learns its tools. It fails when the child cannot be started or does
 // not complete the handshake. A child that exits later is started again on its next call.
 func Start(module, entry string, env []string, mesh Bus, logf func(string, ...any)) (*Launched, error) {
+	if shuttingDown.Load() {
+		return nil, fmt.Errorf("%s's bundle is not started: the runtime is stopping", module)
+	}
 	var mu sync.Mutex
 	var current *child
 	// The child that last subscribed is the one events are handed to: a restarted child subscribes