Switched main terminal from kitty to ghostty

Since the CSR related bugs in ghostty v1 have been corrected, switching
to ghostty as main terminal. I still love kitty, but its font rendering
and some keyboard handling can be janky at times. Ghostty has been
really good so far on my other machine so think i'll switch long-term

home-manager/core/packages.nix

@@ -20,8 +20,6 @@ in {
     ++ (with unstablePkgs; [
       devenv
       lazygit
-      kitty-img
-      kitty-themes
       nixd
     ])
     ++ [

nixos/worklaptop/configuration.nix

@@ -228,7 +228,6 @@
     ++ (with unstablePkgs; [
       just
       ghostty
-      kitty
       libnotify
       neovim
       nushell