Extract primaryUser into module args

hosts/deimos/nixos.nix

@@ -62,7 +62,6 @@
       exec /run/wrappers/bin/fusermount -u "$1"
     '')
 
-    silver-searcher
     file
     nixfmt
     nixd

hosts/mars/home.nix

@@ -1,12 +1,14 @@
-{ pkgs, ... }:
+{ pkgs, primaryUser, ... }:
 {
+  nixpkgs.hostPlatform = "x86_64-darwin";
+
   # TODO: consider
   # https://nest.pijul.com/yonkeltron/macOS-nix-config:main/ZLDSMIXK5XFW6.EIAAA
   # and
   # https://github.com/bgub/nix-macos-starter/tree/main
 
-  home.username = "artem";
-  home.homeDirectory = "/Users/artem";
+  home.username = primaryUser;
+  home.homeDirectory = "/Users/${primaryUser}";
 
   home.packages = with pkgs; [
     secretive