fix: simplify ghost playback start to avoid Jellyfin validation errors

- Remove complex Item object from playback start (was causing 400 errors)
- Send minimal playback info with just ghost UUID and playback state
- Progress reports already working (204 responses)
- Jellyfin will track session without full item details

allstarr/Controllers/JellyfinController.cs

@@ -2290,32 +2290,11 @@ public class JellyfinController : ControllerBase
                     // Generate a deterministic UUID from the external ID
                     var ghostUuid = GenerateUuidFromString(itemId);
                     
-                    // Try to get metadata for the external track to populate the ghost item
+                    // Build minimal playback start with just the ghost UUID
-                    var ghostItem = new
+                    // Don't include the Item object - Jellyfin will just track the session without item details
-                    {
-                        Name = itemName ?? "External Track",
-                        Id = ghostUuid,
-                        Type = "Audio",
-                        MediaType = "Audio",
-                        RunTimeTicks = 0L, // We don't know duration yet
-                        Artists = new[] { provider }, // Use provider as artist for now
-                        Album = "External",
-                        AlbumArtist = provider,
-                        IsFolder = false,
-                        UserData = new
-                        {
-                            PlaybackPositionTicks = positionTicks ?? 0,
-                            PlayCount = 0,
-                            IsFavorite = false,
-                            Played = false
-                        }
-                    };
-                    
-                    // Build playback start with ghost item
                     var playbackStart = new
                     {
                         ItemId = ghostUuid,
-                        Item = ghostItem,
                         PositionTicks = positionTicks ?? 0,
                         CanSeek = true,
                         IsPaused = false,
@@ -2326,7 +2305,7 @@ public class JellyfinController : ControllerBase
                     var playbackJson = JsonSerializer.Serialize(playbackStart);
                     _logger.LogDebug("📤 Sending ghost playback start for external track: {Json}", playbackJson);
                     
-                    // Forward to Jellyfin with ghost item
+                    // Forward to Jellyfin with ghost UUID
                     var (ghostResult, ghostStatusCode) = await _proxyService.PostJsonAsync("Sessions/Playing", playbackJson, Request.Headers);
                     
                     if (ghostStatusCode == 204 || ghostStatusCode == 200)