The ChangeTracker keeps its own per-workflow nodeOutputs cache that is
populated by the 'executed' event and re-applied via restoreOutputs()
during workflow load. Without pruning it on node removal, undo would
clear app.nodeOutputs through the new onNodeRemoved hook only to have
the same entry written back from the tracker's stale cache.
Hook now also derives the execution id for the removed node and
deletes it from the active workflow's tracker cache, recursing through
subgraph contents.
cb75f4e92d