`urlPath` sent the whole app to /files the moment anybody opened a folder — it owns
the pathname, which is right for the Files screen and wrong for a panel. it uses the
platform's new `pathParam` instead, which names a search param and leaves the route
alone.
`?media=` rather than `?path=`: this screen already carries `?section=` and may one
day carry a second browser. a param named after what it addresses cannot collide
with one named after a concept.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>