Feature request: allow different keymap modes when entering via ctrl-r and arrow up

[eclbg]

I use vi mode in my shell and would love to enter atuin in vim-normal mode when launching it with arrow up, and in insert mode when launching it with ctrl-r. This is the most natural to me because it matches the mode I am using in the terminal itself: I can only trigger ctrl-r in insert mode, and I can only use k to go up in normal mode.

I imagine that this could be exposed through a configuration option. I would be happy to work on this myself. What do you think?