feat: Stream Now instant-play of a random track from the nav button

DeepDrftData/TrackManager.cs

@@ -62,6 +62,22 @@ public class TrackManager
         }
     }
 
+    // No base-name conflict, so this is a plain public method. Mirrors the nullable-on-empty
+    // shape of GetById: pass with null when the library has no tracks.
+    public async Task<ResultContainer<TrackDto?>> GetRandom(CancellationToken cancellationToken = default)
+    {
+        try
+        {
+            var entity = await Repository.GetRandomAsync(cancellationToken);
+            return ResultContainer<TrackDto?>.CreatePassResult(
+                entity is null ? null : TrackConverter.Convert(entity));
+        }
+        catch (Exception e)
+        {
+            return ResultContainer<TrackDto?>.CreateFailResult(e.Message);
+        }
+    }
+
     public async Task<ResultContainer<List<TrackDto>>> GetAll()
     {
         try