I still have no idea what that means, but I get called that when I pick up my order at the Palestinian kebab shop. I just assumed it meant "bro" or "buddy" or something. I always just respond with, "thanks, brother (or other pronoun, depending on who's got my heart attack wrap in a bag)".
Yeah in my country it was coopted by the youth and its used to mean bro, brother (affectionate), my love, honey/darling, dude, etc.. something along those lines.
Habibti is used for girls, but most use habibi for both gender.