refactor(nixos): simplify shared defaults

configs/nixos/modules/default.nix

@@ -7,54 +7,33 @@
 }:
 # The shared foundation for every host and guest.
 let
-  inherit (lib) mkOption types;
-  user = config.user;
-
-  pinArgs = prev: {
-    inherit (prev.stdenv.hostPlatform) system;
-    config.allowUnfree = true;
-  };
+  stateVersion = "26.05";
 in
 {
   imports = [ inputs.home-manager.nixosModules.home-manager ];
 
   options.user = {
-    name = mkOption {
-      type = types.str;
+    name = lib.mkOption {
+      type = lib.types.str;
       default = "alexion";
       description = ''
         Primary interactive user for this system.
         This drives the system account and Home Manager user together.
       '';
     };
-    description = mkOption {
-      type = types.str;
-      default = "Alexion";
-      description = "Human-readable description for the primary user.";
-    };
   };
 
   config = {
-    nixpkgs.overlays = [
-      (_final: prev: {
-        unstable = import inputs.nixpkgs-unstable (pinArgs prev);
-        stable = import inputs.nixpkgs-stable (pinArgs prev);
-      })
-    ];
-    nixpkgs.config.allowUnfree = true;
+    system.stateVersion = stateVersion;
 
+    nixpkgs.config.allowUnfree = true;
     nix.settings.experimental-features = [
       "nix-command"
       "flakes"
     ];
 
-    system.stateVersion = "26.05";
-    time.timeZone = "America/New_York";
-    i18n.defaultLocale = "en_GB.UTF-8";
-
-    users.users.${user.name} = {
+    users.users.${config.user.name} = {
       isNormalUser = true;
-      description = user.description;
       extraGroups = [
         "wheel"
         "storage"
@@ -63,16 +42,16 @@ in
 
     users.groups.storage.gid = 10000;
 
+    time.timeZone = "America/New_York";
+    i18n.defaultLocale = "en_GB.UTF-8";
+
     home-manager = {
       useGlobalPkgs = true;
       useUserPackages = true;
-      extraSpecialArgs = {
-        inherit inputs;
-      };
-      users.${user.name} = {
-        home.username = user.name;
-        home.homeDirectory = "/home/${user.name}";
-        home.stateVersion = "26.05";
+      users.${config.user.name} = {
+        home.username = config.user.name;
+        home.homeDirectory = "/home/${config.user.name}";
+        home.stateVersion = stateVersion;
         home.packages = with pkgs; [
           eza
           wget
@@ -85,10 +64,6 @@ in
         command = "eza -alg --color=always --group-directories-first --icons=always";
         abbreviation = false;
       };
-      la = {
-        command = "eza -a --color=always --group-directories-first --icons=always";
-        abbreviation = false;
-      };
       ll = {
         command = "eza -lg --color=always --group-directories-first --icons=always";
         abbreviation = false;
@@ -97,11 +72,6 @@ in
         command = "eza -aT -I '.git' --color=always --group-directories-first --icons=always";
         abbreviation = false;
       };
-      "l." = {
-        command = "eza -a | grep -e '^\\.'";
-        abbreviation = false;
-      };
-
       ".." = "cd ..";
       "..." = "cd ../..";
       "...." = "cd ../../..";