keep the query column visible when scrolling the details table - #1462

The detailed comparison table is wider than the screen, so scrolling right
used to move the query checkbox and the query number out of view, leaving no
way to tell which query a row belongs to.

Make that column sticky. The checkbox and the query number now share a single
cell so a plain `left: 0` is enough — with two cells the second one would need
its offset measured at runtime. Two details keep the scrolled cells from
showing through around the sticky one: an outline covers the table's 1px
border-spacing, and a pseudo-element covers the body padding to its left. The
query number is padded to a fixed width so the checkboxes line up for Q0..Q9
as well, and it keeps its own element so the tooltip still hangs off the name
rather than off the whole cell.

Toggling a query used to re-render only the summary, leaving the detailed
table sorted by the previous ranking; re-render both.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>