Function load_resolve_repos_from_str 

pub fn load_resolve_repos_from_str(
    content: &str,
) -> Result<(Vec<RepoRow>, HashMap<String, String>), String>

What: Parse TOML, validate rows, and build the repo-name map.

Inputs:

• content: Full file contents.

Output:

• Resolved rows and name→filter map, or concatenated error string.

Errors

• Invalid TOML, unsupported preset, validation failures, or duplicate name values.

Details:

• Empty or whitespace-only content yields empty results without error.