feat(player): add IQueueService orchestrating album playback above the single-slot player (P11 11.F)

Queue owns ordered tracks, current index, skip-fwd/back, and auto-advance via the player's TrackEnded hook; binds through Attach (no ctor growth, no service-locator). Player-bar skip controls; empty-queue play unchanged. Adds QueueService unit tests.

DeepDrftPublic.Client/Controls/AudioPlayerProvider.razor.cs

@@ -12,6 +12,7 @@ public partial class AudioPlayerProvider : ComponentBase, IAsyncDisposable
     [Inject] public required ILogger<StreamingAudioPlayerService> Logger { get; set; }
 
     private IStreamingPlayerService? _audioPlayerService;
+    private QueueService? _queueService;
 
     [Parameter] public RenderFragment? ChildContent { get; set; }
 
@@ -29,6 +30,13 @@ public partial class AudioPlayerProvider : ComponentBase, IAsyncDisposable
         // Children must not wrap or replace this callback.
         _audioPlayerService.OnStateChanged = new EventCallback(this, () => InvokeAsync(StateHasChanged));
         // OnTrackSelected will be set by individual child components that need it
+
+        // The queue orchestrates above the single-slot player. The player is not DI-registered
+        // (constructed here), so the queue binds to it via Attach rather than constructor injection —
+        // no construction cycle, no IServiceProvider. Cascaded alongside the player so the bar and a
+        // future up-next panel both read it.
+        _queueService = new QueueService();
+        _queueService.Attach(_audioPlayerService);
     }
 
     /// <summary>
@@ -38,6 +46,11 @@ public partial class AudioPlayerProvider : ComponentBase, IAsyncDisposable
     /// </summary>
     public async ValueTask DisposeAsync()
     {
+        // Dispose the queue first so it unsubscribes from the player's TrackEnded before the
+        // player tears down.
+        _queueService?.Dispose();
+        _queueService = null;
+
         if (_audioPlayerService is IAsyncDisposable disposable)
         {
             await disposable.DisposeAsync();