Yes. I think that’s the only thing I had to change in WP when migrating from the dev domain.
Tech Support was able to get back to me with this response:
This error that you are receiving is generally caused when your WordPress
doesn’t have the correct ownership assigned to the site files. I went
ahead and did a update on all of your site files as well as a permission
update to make sure everything was set correctly.
Sure enough, the updates now work correctly, both in the Dashbord and from WP-CLI. (I had to re-download my plugins, but fortunately I had a list of the missing ones.)
So, it appears that by renaming my dev subdomain folder to the production domain, I didn’t break the site (or the automatic DreamPress updates), but I somehow managed to dissociate my username from my own WP installation.
After some further reading, it seems the proper way to deploy a DreamPress installation from a Staging environment to a Production environment is to:
stage your development version at a DreamPress temporary domain, and then
change the DreamPress temporary domain to your live site by managing the domain through the Dreamhost Panel > DreamPress > Dashboard.