Improve handling of long labels in the graph

When a node renders in the graph, the label might be truncated with an ellipsis. This behavior changes based on your zoom level.

We should either allow some amount of user control or be more flexible in the label width.

Start by locating the graph node label-rendering entry point and reproduce the truncation behavior at different zoom levels. Compare possible user control with more flexible label sizing; done means long labels are handled more usefully across zoom levels, with the chosen behavior verified in the graph UI.

Written by the indexing model from the issue text.