refactor: resync with qbqt baseline and restore genre browser

src/view/maintoolbar.hpp

@@ -44,6 +44,7 @@ private slots:
     void onTrackChanged(const QJsonObject &track);
     void onPositionChanged(quint64 position, quint64 duration);
     void onTrackFinished();
+    void onTrackTransitioned();
     void onQueueChanged();
     void onShuffleToggled(bool checked);