Fix: bare video/audio embeds no longer overflow their column
The embed width rule (.pcms-embed iframe, .folio-embed iframe) only covered
iframes, so the native <video>/<audio> players added in 1.4.0 for bare
.webm/.mp4/.mp3 links kept their intrinsic width and overflowed the content
column. Extend the selector to video/audio (targeted, not '*', so the
client-side player cards' inner elements are untouched). Verified in a browser:
a bare .mp4 <video> now measures the same width as the container and a working
iframe embed, with no horizontal overflow. Reported by Bart.
Co-Authored-By: Claude Opus 4.8 <noreply@…>