Currently the cleanup prompt popup a while. Are there anyway to skip that
step, and just do the clean without prompt?
or a one-click cleanup button?
No. Since you wouldn't like your feeds to be deleted without request.
But it might be a helpful feature to do parts of it (database optimization)
periodically without asking the user…
a cleanup to delete the old news automatically? but not the feed.
There is some level of automated cleanup. You can choose for each feeds to
automatically delete news that have a certain age, or count or just all read
news. Check out the properties for a feed or globally under the feeds