Function route_in_progress 

fn route_in_progress(
    data: &Drawing<'_>,
    start: Pos2,
    waypoints: &[Waypoint],
    end: Pos2,
) -> Vec<TaggedPoint>

Route an in-progress route (start → each waypoint → end) against a freshly built closed router, seeding the endpoints and waypoints so they are graph nodes. Used at commit time, where the exact final geometry (and the route’s own occupancy) matters. The live preview instead routes against a cached router (see RouteTool::preview_route).