Bug PythonDepManager: Dependencies re-installed on every run due to name mismatch

[HavenCTO]

Dependencies reinstall every run because PythonDepManager fails to map import names (e.g., package_name) to distribution names (e.g., package-name), preventing it from detecting existing installations.

Fix: Normalize package naming to handle _ vs. - differences.

originally brought up here - #584 (comment)