Composite node with constant layout

Hi, thank you for this awesome lib. I'm creating a composite node (rect + text) with a constant layout. However the `g` has no `x` and `y` and we must use `transform` but the constant layout `placeNode` doesn't let people to handle this the how do we do that? I have tried to create a graphic and use its `placeNode` function to handle it. However, when I call `addLink` the node in the constant layout `placeNode` function lost its' data. I could create a solution for that but is there a more "native" way?

Read the constant layout implementation and its placeNode path, then trace how addLink causes node data to be lost. Compare the graphic's placeNode usage and determine whether a native transform-based placement path can preserve the node data; done when the composite node remains correctly positioned after addLink.

Written by the indexing model from the issue text.