Lineage assignments should be relative to node in dynamic hierarchy

[alechenninger]

...I think.

Right now we render the hierarchy once for assignments, and that hierarchy is then like it is a static one.

But I think we want each node to have its own, possibly different hierarchy, because when we look at ancestors and descendants, we care about that source at that node. I.e. if I have a change for a source above that node, it should apply, regardless of if it would be in the target's hierarchy.