When set, every interactive edge create prompts the end-user for a label
(stored on the new edge's data.label) using the chosen UI — no callback
needed. An onBeforeEdgeCreate hook, if present, takes over and this is
ignored (the hook can prompt itself via ctx.promptLabel).
When set, every interactive edge create prompts the end-user for a label (stored on the new edge's
data.label) using the chosen UI — no callback needed. AnonBeforeEdgeCreatehook, if present, takes over and this is ignored (the hook can prompt itself viactx.promptLabel).