The force layout settled roughly square, so in a wide band the graph sat as a
small island. Vertical centring now pulls nearly three times as hard as
horizontal and the seed sits on an ellipse, which settles at about 2.2:1
without stretching the circles or the edges.
The graph also slid in on load: the rebuild fit ran with a 300ms duration, so
React Flow animated the pan from its default viewport to the content. The fit
is instant now, and the canvas grows in from the centre with `scaleIn` once it
has a layout.
The pinned chart header said "Esc clears", which a phone cannot act on. It
carries the same "× Clear" button as the list header instead; Escape still
works.