Publish the libraries a few at a time

[sjoelund]

Once the tests are done, the run publishes one library at a time, and what that costs is not the copying but waiting for the far side: each library asks rsync four times over ssh, and the one that matters lists a remote directory of tens of thousands of files to honour --delete-excluded.

Three things were paid for per library and are now paid for once:

What	Before	After
git log of this repository	once per lib	once
git log of the reference files	once per lib	once per dir
rsync connections to make the dirs	3	1

The directories are made in one connection by telling rsync -R where the relative part of the source path starts, so emptydir/./<lib>/files creates the branch, the library and its files directory at once instead of one rsync per level.

The libraries are then published four at a time. Not more: each one is an ssh connection of its own, and sshd allows ten unauthenticated connections by default.

The loop body became a function, which also stops it shadowing the stats dictionary of the run with a list of its own.

Assisted-by: Claude Opus 5