setup_model_provider() had 800+ lines of duplicated provider handling
that reimplemented the same credential prompting, OAuth flows, and model
selection that hermes model already provides via the _model_flow_*
functions. Every new provider had to be added in both places, and the
two implementations diverged in config persistence (setup.py did raw
YAML writes, _set_model_provider, and _update_config_for_provider
depending on the provider — main.py used its own load/save cycle).
This caused the #4172 bug: _model_flow_custom saved config to disk but
the wizard's final save_config(config) overwrote it with stale values.
Fix: extract the core of cmd_model() into select_provider_and_model()
and have setup_model_provider() call it. After the call, re-sync the
wizard's config dict from disk. Deletes ~800 lines of duplicated
provider handling from setup.py.
Also fixes cmd_model() double-AuthError crash on fresh installs with
no API keys configured.
491e79bca9