Some screens fetch items with a fields filter (e.g. series detail uses
["MediaSources", "MediaStreams", "Overview", "Trickplay"]) and pass the
resulting DTO straight into the download flow. Jellyfin only returns
Chapters in that case when explicitly listed, so the snapshot we store
under DownloadedItem.item carries Chapters: undefined and the offline
player renders no ticks / list / current-chapter label.
initiateDownload now re-fetches the item via getUserLibraryApi.getItem
(no fields filter -> full DTO incl. Chapters) when Chapters is missing,
and uses the enriched item for both getDownloadUrl and the snapshot. If
the refresh call fails we log and fall back to the original item — the
download itself still proceeds.
Trickplay offline already worked (useTrickplay reads trickPlayData.path
from the downloaded sheets).
558fb41833