New tool that classifies URLs by domain and delegates to pos media mp3
(audio) or pos media mp4 (video). Listener gains URL detection step
between prefix map and AI bridge — bare URLs auto-download.
Domain rules: music.youtube.com/soundcloud/bandcamp → mp3,
youtube/vimeo/twitch → mp4 --best, unknown → configurable default.
28 test cases / 70 assertions / 0 failed.
make gen && make check green, make lint 0 FAIL / 0 WARN.