Function preview_add_repository 

pub fn preview_add_repository(
    source: &str,
    alias: &str,
    repository_path: &str,
) -> Result<ManifestEdit, ManifestEditError>

Previews adding a minimal repository entry while preserving unrelated bytes.

Errors

Returns ManifestEditError for invalid aliases, duplicate aliases, unsupported layout, or invalid generated manifests.