Currently not, sadly. However, now that fletcher has support for cetz anchors, this could be easily added by allowing edges to be named and giving them path anchors, like in cetz:
#cetz.canvas({
import cetz.draw
draw.line((0,0), (1,2), (3,1), stroke: 1pt, name: "hi")
draw.content("hi.75%", $ circle $)
})
I’ve just made a feature request for it: Edge names and anchors · Issue #96 · Jollywatt/typst-fletcher · GitHub