fix: a projected edge stays the edge that was picked when its body changes (#730)

A sketch's link to a projected edge now keeps the edge's persistent name and finds it by that name when the body changes, instead of taking whichever edge ends up nearest its point.

crates/sketch/src/wire.rs

@@ -196,7 +196,7 @@ impl Sketch {
         }
         let id = if geom.is_empty() {
             let id = self.fresh("j")?;
-            self.links.push(Link { id: id.clone(), kind, source, face_name: None, auto_face: false, lost: false });
+            self.links.push(Link { id: id.clone(), kind, source, face_name: None, edge_name: None, auto_face: false, lost: false });
             id
         } else {
             self.add_link(kind, source, geom)?