[BUG] Undo/redo breaks after copy–paste in imported service

[matKlju]

Bug description:
After importing a service, copying and pasting an element causes undo/redo to appear unresponsive, but in reality pasted nodes are added on top of existing nodes (layered in the same position). This makes it look like nothing happened and breaks expected undo/redo behavior.

Expected behavior:

• Pasted nodes should be placed with an offset or visible position
• Undo/redo should clearly revert and restore pasted nodes
• No hidden/layered nodes should be created

Screenshots:

undoRedo-copyPaste.zip

Additional information:
Repro steps:

1. Import a service
2. Copy an element
3. Paste the element
   • Result: new node is added on top of the existing one (same coordinates)
4. Try Undo / Redo

Impact:

• Undo/redo seems broken
• Hidden overlapping nodes cause confusing canvas state