feat(zsh): add zsh-vi-mode

shell/zsh.nix

@@ -1,4 +1,4 @@
-{ theme, ... }:
+{ pkgs, theme, ... }:
 let
   zsh_autosuggest_highlight_style = if theme == "light" then "fg=180" else "fg=10";
 in
@@ -20,6 +20,12 @@ in
       }
 
       precmd_functions+=(set_win_title)
+
+      function zvm_config() {
+        ZVM_INIT_MODE=sourcing
+      }
+
+      source ${pkgs.zsh-vi-mode}/share/zsh-vi-mode/zsh-vi-mode.plugin.zsh
     '';
   };
 }