Function resolve_remote 

pub fn resolve_remote(cfg: &LayeredConfig, name: &str) -> Option<ResolvedRemote>

Resolve a remote NAME to its endpoint + provenance.

• default (or an empty name): the flat remote_endpoint; chosen by the repo iff the repo layer set it.
• any other name: a remote.<name>.url entry. Named remotes are stored repo-scoped, so a named remote present in the repo layer is repo_chosen; one present only in the user layer is not.

Returns None when the name is unknown / its URL is empty.