Enum-like settings whose allowed values were only listed in a comment are
now Literal types, so a typo fails at startup with a message naming the
allowed values instead of falling through to a default with a warning
(or, for VECTOR_STORE, failing on first use):
AUTH_TYPE, VECTOR_STORE, STORAGE_TYPE, URL_STRATEGY, OCR_BACKEND,
OCR_ENGINE, SANDBOX_BACKEND, DOC_PARSER_ENGINE, TTS_PROVIDER, STT_PROVIDER
Each keeps a before-validator that strips and lower-cases the value, since
the registries that consume them already lower-cased at the use site, and
AUTH_TYPE maps the "None"/"none"/"" spellings a .env file carries to None
(it was the string "None" before, which only worked because nothing
compared against it). An empty TTS/STT provider still means "off".
LLM_PROVIDER stays a plain str because providers are plugin-extensible.
Containers are typed (dict[str, int], list[str], dict[str, Any]) instead
of bare dict/list, six fields that were Optional with a non-None default
are plain, and integer settings whose description already states a range
carry it as a constraint (ge=0 for "0 disables", ge=1 for counts that
cannot be zero, 0 < threshold <= 1).
arc53-machine
95d0799494