Function default_component_sources_with_hub_version 

pub fn default_component_sources_with_hub_version(
    project_dir: &Path,
    hub_version: Option<&str>,
) -> Result<Vec<ComponentSource>, String>

Same as default_component_sources, but lets the caller pick which Hub version to fetch when default resolution needs the network (i.e. no in-repo hub/components on disk). This is the seam the CLI’s --hub-version flag threads through; None means “this binary’s own version”, the ordinary default.