Added playlist renaming functionality.

Harmonia.Core/Playlists/Playlist.cs

@@ -14,6 +14,24 @@ public class Playlist
 
     public event EventHandler<PlaylistUpdatedEventArgs>? PlaylistUpdated;
 
+    public void SetName(string name)
+    {
+        if (string.Equals(Name, name, StringComparison.Ordinal))
+            return;
+
+        Name = name;
+
+        PlaylistUpdatedEventArgs eventArgs = new()
+        {
+            Action = PlaylistUpdateAction.Rename,
+            Index = -1,
+            Count = 0,
+            Songs = []
+        };
+
+        PlaylistUpdated?.Invoke(this, eventArgs);
+    }
+
     public void Lock()
     {
         if (IsLocked)