6883cd0969
Three index bugs in PlayQueueManager, two of which leave PlayingItemIndex out of bounds, making every subsequent Buffering/Ready request throw and leaving the group unusable until it empties: - RemoveFromPlaylist did not compensate for removed items preceding the playing item: removing the playing item together with earlier items could select the wrong item or crash with an out-of-bounds index. - Next/Previous on an empty playlist with RepeatOne/RepeatAll reported success or set PlayingItemIndex to 0 on an empty list, crashing downstream in Group and corrupting the index. - SetPlayingItemByIndex accepted an index equal to the playlist count (latent off-by-one, callers currently pre-validate).