I got pretty confused about why I can't set auth.method from the config
file (and also why there were no docs saying what the JSON/YAML/etc key
would even be).
Document that this doesn't work to try to prevent future confusion here.
Caveat: I wrote this documentation by hand, but I did not actually read
the code carefully enough to have figured this out myself. I am
trusting the claims made by an LLM coding agent (which do at least seem
to match empirical evidence).