The agent icon was a 26px <img> inline in the card head, hidden via
onerror when a stopped container's web server didn't answer — which
collapsed the slot and shifted the row.
Restructure the live container card as icon-left / body-right:
- the icon is a background-image div with aspect-ratio 1 and
align-self stretch — full card height, square, and (being a
background) it has no intrinsic size, so loading or failing it
can never reflow the row;
- a failed load (stopped container) falls through to a placeholder
fill instead of collapsing;
- the three content lines move into a .card-body column.
Tombstone rows keep the plain stacked layout (:not(.tombstone)).
closes#177
9abcda280a