- _load_models_cache_from_disk: resolve _get_models_cache_path() once
(was called twice — exists() then open()) (greptile P2).
- conftest: use a _MISSING sentinel for the _active_profile restore guard so
it restores whenever api.profiles was importable pre-test, independent of the
value (greptile P2; _active_profile defaults to 'default' so the prior
is-not-None guard was functionally fine but technically value-dependent).
Co-authored-by: nesquena-hermes <nesquena-hermes@users.noreply.github.com>