fixes#560
When the CLI input has provider/id format (e.g. zai/glm-5), the exact
match now checks decomposed provider+id first (provider=zai, id=glm-5)
before falling back to flat model.id string match. This prevents
vercel-ai-gateway's 'zai/glm-5' model from winning over the zai
provider's 'glm-5' model due to Array.find catalog ordering.
Keeps getAll() rather than switching to getAvailable() to preserve
the --api-key ephemeral flow, where auth is injected after resolution.
