Function parse_script_with_modules 

pub fn parse_script_with_modules(
    input: &str,
    modules: ModuleTable,
) -> Result<Vec<Step>, Error>

Parse with a module provenance table so calls resolve statically: qualified MODULE::NAME checks membership, bare NAME resolves through SCRIPT definitions and IMPORTed modules. Reserved covers builtins plus every table module, so FUNC shadowing any of them fails here; hosts unknown at parse time fall back to the runtime define_func guard.