When switching FROM Codex/Nous/custom TO OpenRouter via 'hermes setup',
the old provider stayed active because setup only saved the API key but
never updated config.yaml or auth.json. This caused resolve_provider()
to keep returning the old provider (e.g. openai-codex) even after the
user selected OpenRouter.
Fix: the OpenRouter path in setup now deactivates any OAuth provider
in auth.json and writes model.provider='openrouter' to config.yaml,
matching what all other provider paths already do.