The download progress toast sits in the bottom-right corner on top of the
comment composer, blocking the voice-recording button and the comment box for
the whole duration of a download.
Render it through toast.custom so it can be collapsed to a small pill (percent
+ spinner) and expanded again while the download keeps running. The minimized
choice sticks for the rest of the session. The sonner <li> is click-through, so
only the panel itself covers the controls underneath.
Also dismiss the panel on failure — it had duration: Infinity and used to stay
on screen forever after an error.
