Illustrates how diff works with file-per-root persistence when root nodes differ only in IDs.

As of 2025.3 comparing main and feature branches will show HelloWorld class as added (in MPS model viewer), but in fact it was added in both branches and only node IDs are different. Toggling "Show non-functional ID changes" option does not change how the changes are presented.

Since both branches store the root node in the same file (HelloWorld.mpsr), it would be useful to show that the root is present in both branches and only the IDs differ.