63561ce719
Add scripts/check_new_py_files.py, which enforces ADK's private-by-default policy: a newly-added Python file under src/google/adk/ must have a '_'-prefixed basename (expose public API via __init__.py / __all__ instead). Newly-added files are detected by comparing the checked-out tree against a baseline source tree, so the check needs no git history. Co-authored-by: Haran Rajkumar <haranrk@google.com> PiperOrigin-RevId: 943513793