pub async fn playback_mode_set_transferring(
manager: State<'_, PlaybackModeManagerWrapper>,
transferring: bool,
) -> Result<(), String>Expand description
Set the transferring flag on the playback mode manager.
Used by the frontend remote->local flow to mark the whole two-step sequence
as a transfer, so player_play_tracks starts LOCAL playback instead of
casting back to the remote session it’s leaving. Always pair true with a
later false (including on error) so the flag can’t stick.