fix: PlayRelease always materialises a defensive copy so Items alias can't wipe the queue on jump; add aliasing regression test

DeepDrftTests/QueueServiceTests.cs

@@ -144,6 +144,33 @@ public class QueueServiceTests
         });
     }
 
+    [Test]
+    public async Task PlayRelease_ViaLiveQueueItems_PreservesTracksAndJumpsToIndex()
+    {
+        // Regression guard for the aliasing bug: OnQueueJump calls PlayRelease(QueueService.Items, index).
+        // Items returns the backing list directly; without a defensive copy, the cast
+        // "tracks as IReadOnlyList<TrackDto>" aliases _items, so _items.Clear() also clears list,
+        // and _items.AddRange(list) adds nothing — wiping the queue and playing nothing.
+        await _queue.PlayRelease(Tracks(4)); // populate the live queue
+
+        // Jump to index 2 via the live Items reference, exactly as OnQueueJump does.
+        await _queue.PlayRelease(_queue.Items, 2);
+
+        Assert.Multiple(() =>
+        {
+            // The queue must survive — all four tracks still present, in order.
+            Assert.That(_queue.Items, Has.Count.EqualTo(4));
+            Assert.That(_queue.Items.Select(t => t.EntryKey),
+                Is.EqualTo(new[] { "track-1", "track-2", "track-3", "track-4" }));
+            // CurrentIndex must be the jumped-to slot.
+            Assert.That(_queue.CurrentIndex, Is.EqualTo(2));
+            // Current must be the right track.
+            Assert.That(_queue.Current!.EntryKey, Is.EqualTo("track-3"));
+            // The player must have streamed the jumped-to track.
+            Assert.That(_player.SelectedTracks.Last().EntryKey, Is.EqualTo("track-3"));
+        });
+    }
+
     // --- Arm: prerender-safe load without streaming (release embed) ---
 
     [Test]