Biding my time while desymlink gells in my head..

Fixed a bug in the assistant's local pairing that rejected ssh keys with a period in the comment.

Fixed a bug in the assistant that made it try to drop content from remotes that didn't have it, and avoided a drop failure crashing a whole assistant thread.

Made --auto behave better when preferred content is set.

Looked into making the transfer queue allow running multiple transfers at the same time, ie, one per remote. This seems to essentially mean splitting the queue into per remote queues. There are some complexities, and I decided not to dive into working through it right now, since it'd be a distraction from thinking about desymlink. Will revisit it later.

Allow specifying a port when setting up a ssh remote.

While doing that, noticed that the assistant fails to transfer files to sync to a ssh remote that was just added. That got broken while optimising reconnecting with a remote; fixed it.