Dispose the viewer query when the alias changes so navigating between
documents shows the skeleton instead of the previous document. Guard the
export completion against the current id so a slow export can't overwrite
a newer document's preview. Split the documents tab state into requested
and loaded refs so an out-of-order or failed refetch can't leave the list
showing a different tab than the toolbar.
Signed-off-by: Émile Ré <emile@probo.com>
6abe5f84f8