Previously the file bubble wrapped JS middle-ellipsis in CSS truncate,
so narrow containers silently clipped the tail+extension, leaving
e.g. "25cb264a-e06…." instead of "25cb264a-e06…811a.jpg".
Split the displayed name into a shrinking head (with CSS truncate)
and a non-shrinking tail (last 4 base chars + extension). The browser
now decides how much head to clip while the suffix is always visible.
cc9f0a5730