Batch of visually verified Web UI fixes: trigger-menu z-index over the
resize handle (#3228, #3229), input scrollbar offset, tool-row file
links and diff stats (#3230), @ menu crumb alignment, light-mode
divider, and @ menu flicker while typing (#3234) via
stale-while-revalidate — a refinement hit keeps the previous items and
highlight on screen until the new generation settles, so neither the
skeleton nor the first-row focus blinks per keystroke.