pub fn resolve_agent(cfg: &Config, agent_name: &str) -> Result<ResolvedAgent>Expand description
Walk cfg.agents -> models -> providers to resolve every knob the agent
loop needs. Bails with a descriptive error if a reference is dangling or
the api-key env var is unset.
Each lookup is re-checked here – the function does not assume
cfg.validate() was called – so errors carry the resolution context
(which agent, which model) regardless.