refactor(nixos): inline module enable conditions

configs/nixos/modules/shell/yazi.nix

@@ -6,13 +6,12 @@
 }:
 # Yazi, a terminal file manager.
 let
-  cfg = config.modules.shell.yazi; # NOLINT(let_order)
   user = config.user.name;
 in
 {
   options.modules.shell.yazi.enable = lib.mkEnableOption "Yazi, a terminal file manager";
 
-  config = lib.mkIf cfg.enable {
+  config = lib.mkIf config.modules.shell.yazi.enable {
     home-manager.users.${user}.programs.yazi = {
       enable = true;
       enableFishIntegration = true;