Function build_wizard 

pub fn build_wizard(env: &SetupEnv) -> Wizard

Build a wizard against env.

The base config comes from reading the file, deliberately not from Config::load(): load folds $ANTHROPIC_API_KEY and friends in, and the old wizard re-serialized the whole struct - quietly writing into ~/.leviath/config.toml a key the user had chosen to keep in their environment. Those are tracked separately and shown as such.