Function get_string 

pub fn get_string(
    adapters_dir: &Path,
    option: &str,
    key_path: &str,
) -> Result<Option<Value>, RegistryError>

Read a [strings] dot-path from an adapter option’s merged view — the spt adapter get-string <adapter-option> <key.path> resolver. Resolves the option (bare = parent, else shipped/local overlay) exactly as every other consumer, then dot-path-traverses the merged [strings] tree. Ok(None) = the key is absent (a clean “not set”, distinct from an unresolvable option).