gpui runs the click of every pressed element under the pointer, so a
press on a finished download's Show button also opened the file through
the pressable row. The actions' box stops the press on mouse down, so
the row starts no click of its own.
A file on its way is a Transfer with a state: waiting, moving at a rate,
paused, done or failed with a reason. One row draws it for the queue and
the downloads: its icon, its way, a bar while it moves or waits paused, a
status with the time left, and only the actions its state allows.
TransferQueue counts what moves and waits. DownloadManager keeps the
finished below under Clear, opening on a press and showing their folder.
FileOperationProgress tells a copy or move with its bar, time left and
current file, its header wrapping by the header rule; a failure speaks in
the danger tone. StorageUsage points to data_display's UsageBar.
ZacharyZhang-NY