TL;DR - I was able to produce and publish sphinx based documentation from the work in
DM-11216 after some leg work.
Details - After banging my head on file encoding errors from sphinx that didn't identify the source file, I kludged astropy_helpers to force the encoding on all opened files to utf-8, which resolved the encoding error messages. I was gong to PR this upstream but discovered that an identify change had already been made and was including in recent 2.x and the 3.0 release as of about a week ago. Updating the version of astropy_helpers used by documenteer was [is hopefully] the permanent fix.
A PoC jenkins job named sqre/infrastructure/documenteer, that builds the sphinx docs from a published stack release docker image and publishes them via ltd-mason, has been tested and deployed to production. Along with sqre/infrastructure/build-ltd-mason, which produces the image used to run ltd-mason.
The weekly/nightly release pipelines have been updated to trigger s/i/documenteer. However, this is as-of-yet untested, so this ticket is being placed into self-review in order to follow up on the results of the nightly build tomorrow.