Update authorization policies for SyncPlay

Jellyfin.Data/Enums/SyncPlayUserAccessType.cs

@@ -0,0 +1,23 @@
+namespace Jellyfin.Data.Enums
+{
+    /// <summary>
+    /// Enum SyncPlayUserAccessType.
+    /// </summary>
+    public enum SyncPlayUserAccessType
+    {
+        /// <summary>
+        /// User can create groups and join them.
+        /// </summary>
+        CreateAndJoinGroups = 0,
+
+        /// <summary>
+        /// User can only join already existing groups.
+        /// </summary>
+        JoinGroups = 1,
+
+        /// <summary>
+        /// SyncPlay is disabled for the user.
+        /// </summary>
+        None = 2
+    }
+}