Notification sound added. Docs updated.

internal/speech/recovery_test.go

@@ -72,6 +72,7 @@ func TestRecoveryKeepsAdmissionResponsiveAndDropsOutageSpeech(t *testing.T) {
 	service.Toggle_mute()
 	service.Say_with_pitch("fresh", 60)
 	wait_event(t, fresh.changed, "sent:fresh")
+	wait_event(t, fresh.changed, "pitch:10")
 	fresh.mu.Lock()
 	joined := strings.Join(fresh.events, "|")
 	fresh.mu.Unlock()