feat: initial qobuz-qt source

Lightweight Qt6 desktop client for Qobuz with a Rust audio backend
(Symphonia/CPAL via staticlib FFI). Mirrors the spotify-qt layout:
toolbar with playback controls, library/context docks on the left,
tabbed search side panel on the right, queue panel, now-playing dock.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/list/tracks.hpp

@@ -2,6 +2,7 @@
 
 #include "../model/tracklistmodel.hpp"
 #include "../backend/qobuzbackend.hpp"
+#include "../playqueue.hpp"
 
 #include <QTreeView>
 #include <QJsonArray>
@@ -9,32 +10,32 @@
 
 namespace List
 {
-    /// Track list view — mirrors the spotify-qt List::Tracks widget.
-    /// Displays a flat list of tracks for a playlist, album, search result, etc.
     class Tracks : public QTreeView
     {
         Q_OBJECT
 
     public:
-        explicit Tracks(QobuzBackend *backend, QWidget *parent = nullptr);
+        explicit Tracks(QobuzBackend *backend, PlayQueue *queue, QWidget *parent = nullptr);
 
         void loadTracks(const QJsonArray &tracks);
         void loadAlbum(const QJsonObject &album);
         void loadPlaylist(const QJsonObject &playlist);
         void loadSearchTracks(const QJsonArray &tracks);
 
-        void setCurrentTrackId(qint64 id);
+        /// Called when the backend fires EV_TRACK_CHANGED so the playing row is highlighted.
+        void setPlayingTrackId(qint64 id);
 
     signals:
         void playTrackRequested(qint64 trackId);
 
     private:
-        TrackListModel *m_model   = nullptr;
-        QobuzBackend   *m_backend = nullptr;
-        qint64          m_currentTrackId = 0;
+        TrackListModel *m_model     = nullptr;
+        QobuzBackend   *m_backend   = nullptr;
+        PlayQueue      *m_queue     = nullptr;
+        qint64          m_playingId = 0;
 
         void onDoubleClicked(const QModelIndex &index);
         void onContextMenu(const QPoint &pos);
-        void resizeColumnsToContent();
+        void syncQueueToModel();
     };
 }