- Both audio_file and speaker.media_player now use functools.partial to
bind path_for=_compute_local_file_path instead of an inline lambda.
- download_content_many's dedup loop becomes a dict comprehension.
Last-URL wins now (dict-comp semantics) instead of first-URL; in
practice duplicate paths only arise when the URL itself is duplicated,
so the choice is meaningless. Test updated accordingly.