How to tell iterm2 to use emacs mode, not vi mode

I've recently switched from Hyper terminal (no longer maintained) to iterm2. I'm surprised that iterm2 seems to be using vi mode: instead of going to start and end of line when I press ctrl+a/ctrl+e it emits literal ^A and ^E. I don't remember ever configuring vi mode on purpose. iterm2's configuration GUI overwhelms me. I've tested running zsh in factory mode (zsh -f), and even there iterm2 uses vi mode. In contrast, when I use Hyper or the inbuilt terminal, zsh is in default readline mode. How can I fix this? I've gone through iterm2 documentation and issue tracker and couldn't find anything. Interestingly, when I run zsh -f in inbuilt Terminal, it _is_ in vi mode. Similar question over at superuser, which has been open for 10 years without answer: https://superuser.com/questions/840134/unintentional-vi-mode-in-iterm-on-mac