Add whole-release embeds to FramePlayer and un-gate the release embed share affordance

The queue gains an armed-but-idle state (Arm/Start) so a release embed stages track 0 prerender-safe, then queues the full release on first play and auto-advances.

DeepDrftPublic.Client/Services/QueueService.cs

@@ -26,6 +26,8 @@ public sealed class QueueService : IQueueService, IDisposable
 
     public int CurrentIndex { get; private set; } = -1;
 
+    public bool IsArmed { get; private set; }
+
     public TrackDto? Current =>
         CurrentIndex >= 0 && CurrentIndex < _items.Count ? _items[CurrentIndex] : null;
 
@@ -62,11 +64,34 @@ public sealed class QueueService : IQueueService, IDisposable
         _items.Clear();
         _items.AddRange(list);
         CurrentIndex = start;
+        // Playback is now starting for real, so the queue is no longer merely armed.
+        IsArmed = false;
         QueueChanged?.Invoke();
 
         await PlayCurrent();
     }
 
+    public void Arm(IEnumerable<TrackDto> tracks)
+    {
+        var list = tracks as IReadOnlyList<TrackDto> ?? tracks.ToList();
+        if (list.Count == 0) return;
+
+        _items.Clear();
+        _items.AddRange(list);
+        CurrentIndex = 0;
+        IsArmed = true;
+        // No PlayCurrent: arming is interop-free state only. The first play gesture drives Start().
+        QueueChanged?.Invoke();
+    }
+
+    public async Task Start()
+    {
+        if (!IsArmed) return;
+        IsArmed = false;
+        QueueChanged?.Invoke();
+        await PlayCurrent();
+    }
+
     public void Enqueue(TrackDto track)
     {
         _items.Add(track);
@@ -85,6 +110,7 @@ public sealed class QueueService : IQueueService, IDisposable
     {
         if (!HasNext) return;
         CurrentIndex++;
+        IsArmed = false;
         QueueChanged?.Invoke();
         await PlayCurrent();
     }
@@ -93,6 +119,7 @@ public sealed class QueueService : IQueueService, IDisposable
     {
         if (!HasPrevious) return;
         CurrentIndex--;
+        IsArmed = false;
         QueueChanged?.Invoke();
         await PlayCurrent();
     }
@@ -102,6 +129,7 @@ public sealed class QueueService : IQueueService, IDisposable
         if (_items.Count == 0 && CurrentIndex == -1) return;
         _items.Clear();
         CurrentIndex = -1;
+        IsArmed = false;
         QueueChanged?.Invoke();
     }