Function collect_exported_function_names_from_source 

pub fn collect_exported_function_names_from_source(
    module_path: &str,
    source: &str,
) -> Result<Vec<String>>

Collect exported function names from module source using canonical module-loader export semantics.

This keeps extension module namespace behavior (use mod; mod.fn(...)) aligned with normal module loading and avoids ad-hoc export parsing.