Plugin-only providers (commandcode, tencent-tokenhub, ...) are absent from
models.dev and HERMES_OVERLAYS, so resolve_provider_full returned None and
/model switches failed with "Unknown provider ..." even though the picker
lists them (CANONICAL_PROVIDERS auto-extends from the same registry).
Fall back to providers.get_provider_profile() before giving up, mapping the
profile api_mode to the ProviderDef transport.
The model picker's generic live-fetch path (hermes_cli/models.py
provider_model_ids) calls profile.fetch_models(api_key=..., base_url=...).
Both CommandCode overrides only accepted api_key/timeout, so every picker
open raised TypeError, which was silently swallowed, leaving the provider
with zero models.
Match the base ProviderProfile.fetch_models signature (base_url kwarg) and
add a regression test asserting both profiles accept it.