"Share Contact…" does not convey what the menu does in MUCs
I think the "share contact" with QR code menu is nice, but there is a wording problem. It's OK for 1:1 chats, but for MUCs it does not make sense. Maybe it should be renamed "share group chat" for MUCs? Also, for members-only MUCs, maybe add a warning that scanning the QR or clicking the xmpp:
IRI can only work if you're member of the group?