The agents card lists every detected agent, and on most machines
most of those rows read "default" — nothing has been set on them.
This keeps the ones that have a model or an effort of their own and
folds the rest behind a "Show N more" row at the end of the list.
A magpie with nothing set yet still shows every agent, since folding
all of them would leave the card empty. The toggle only appears when
something is actually folded.
Frontend only — three files under internal/gui/assets, no change to
state() or to settings.