closes#97
when copying group nodes across decks (including in and out of groups), they become unique and completely independent copies of the original. this is done recursively, so in the case of copying:
- group X
- contained in Deck A
- has another group Z
into Deck B, group X will become group Y, group Z will become group W.
there is a rare bug that will sometimes cause the deck to save with no groups at all, which i haven't been able to hunt down and don't know how to replicate at the moment.
Reviewed-on: https://codeberg.org/StreamGraph/StreamGraph/pulls/143
Co-authored-by: Lera Elvoé <yagich@poto.cafe>
Co-committed-by: Lera Elvoé <yagich@poto.cafe>