chore: import MusifyBackend into monorepo (preserving history)

git-subtree-dir: MusifyBackend
git-subtree-mainline: 6829e769ed
git-subtree-split: ed7b00c2cc

MusifyBackend/Application/Events/UpdateTrackAudioEvent.cs

@@ -0,0 +1,9 @@
+namespace Musify.Application.Events
+{
+    public record UpdateTrackAudioEvent(
+        Guid TrackId,
+        string SourceBucket,
+        string SourceKey,
+        string DestinationBucket,
+        string DestinationFolderKey);
+}