Bundled pure-Python dependencies (no pip / no internet required at runtime).
Loaded via vendor.py, which prepends this libs/ folder to sys.path.

  pyserial   3.5     -> serial/        (MIT/BSD)  port enumeration + reading
  pyais      3.1.0   -> pyais/         (MIT)      AIS decode/encode
  attrs      26.1.0  -> attr/ attrs/   (MIT)      pyais runtime dependency

All are py3 pure-Python and cross-platform (Windows/macOS/Linux). License texts
are alongside each as *_LICENSE.txt. To update a library, replace its package
folder here with the contents of a newer -py3-none-any wheel (a wheel is a zip).
