Function blast_radius_for_project 

pub fn blast_radius_for_project(
    project_dir: &Path,
    node: &str,
) -> Result<Option<HostImpact>, String>

Fetch the bound layer’s reported impact for node. Resolves the context the same way compile_project_to_ir does (profile.yml → context binding → ContextLoader), but stops short of a full compile. Nothing is computed here: the answer is whatever the layer supplied, and a layer that supplied no analysis is an error rather than an empty radius.