When copying a component containing a swapped nested component, the
copy operation was not preserving the swap information correctly. This
caused referential integrity errors when pasting the component.
The fix detects when a subinstance head's shape-ref is being advanced
during copy and preserves the original shape-ref as a swap-slot. This
ensures referential integrity is maintained when the copy is pasted in
a context where the parent's near main is reachable.
Closes#9547