fix: use stacked layout for DataBrowser on narrow screens

The CSS grid layout with minmax() minimum widths summed to more than
narrow screen widths, causing columns to overlap on mobile devices.

Switch to a stacked card layout on screens narrower than 768px where
each row displays fields vertically with labels. Disable virtualization
on narrow screens since the stacked layout has variable row heights.

addresses #2281

Author: dirkwa