feat(nixos): add desktop module with non-portable home-manager profile

Add system/modules/desktop.nix (counterpart to laptop.nix): imports the
workstation base and uses wired NetworkManager instead of iwd.

Thread a `portable` flag (default true) through mkHost into specialArgs and
home-manager.extraSpecialArgs, mirroring username/fullName. lyrathorpe/home/
sway.nix consumes it to drop mobile components on desktop hosts:
- status bar swaps the battery block for CPU temperature + network throughput
- screen-brightness keybindings are omitted (no internal backlight)

No host uses desktop.nix yet; a future desktop host imports it and sets
`portable = false`. Verified by evaluating sway.nix both ways:
laptop -> [.. sound battery time] + brightness keys;
desktop -> [.. temperature net sound time], no brightness keys.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

flake.nix

@@ -98,16 +98,34 @@
             fullName,
             modules,
             homeModules,
+            # Host form factor. Laptops inherit the default; a desktop host sets
+            # `portable = false` to drop mobile components (battery block,
+            # brightness keys) from the home-manager Sway config.
+            portable ? true,
           }:
           nixpkgs.lib.nixosSystem {
             inherit system;
-            specialArgs = { inherit inputs username fullName; };
+            specialArgs = {
+              inherit
+                inputs
+                username
+                fullName
+                portable
+                ;
+            };
             modules =
               baseModules
               ++ modules
               ++ [
                 {
-                  home-manager.extraSpecialArgs = { inherit inputs username fullName; };
+                  home-manager.extraSpecialArgs = {
+                    inherit
+                      inputs
+                      username
+                      fullName
+                      portable
+                      ;
+                  };
                   home-manager.users.${username}.imports = homeModules;
                 }
               ];

lyrathorpe/home/sway.nix

@@ -6,7 +6,14 @@
 # pulling a second Sway. home-manager owns the user config (~/.config/sway) and
 # wires the systemd user session (sway-session.target), which is what lets the
 # swayidle/dunst user services start with the desktop.
-{ pkgs, lib, ... }:
+{
+  pkgs,
+  lib,
+  # Threaded from mkHost (flake.nix). Desktop hosts set this false to drop
+  # mobile components (battery block, screen-brightness keys).
+  portable ? true,
+  ...
+}:
 {
   wayland.windowManager.sway = {
     enable = true;
@@ -42,15 +49,20 @@
         }
       ];
 
-      keybindings = lib.mkOptionDefault {
+      keybindings = lib.mkOptionDefault (
+        {
           "${modifier}+l" = "exec ${pkgs.swaylock}/bin/swaylock -f";
           "Print" = "exec ${pkgs.grim}/bin/grim ~/screenshot-$(date +%F-%H%M%S).png";
-        "XF86MonBrightnessUp" = "exec ${pkgs.brightnessctl}/bin/brightnessctl set 5%+";
-        "XF86MonBrightnessDown" = "exec ${pkgs.brightnessctl}/bin/brightnessctl set 5%-";
           "XF86AudioRaiseVolume" = "exec ${pkgs.wireplumber}/bin/wpctl set-volume @DEFAULT_AUDIO_SINK@ 5%+";
           "XF86AudioLowerVolume" = "exec ${pkgs.wireplumber}/bin/wpctl set-volume @DEFAULT_AUDIO_SINK@ 5%-";
           "XF86AudioMute" = "exec ${pkgs.wireplumber}/bin/wpctl set-mute @DEFAULT_AUDIO_SINK@ toggle";
-      };
+        }
+        # Screen backlight: laptops only (no internal backlight on a desktop).
+        // lib.optionalAttrs portable {
+          "XF86MonBrightnessUp" = "exec ${pkgs.brightnessctl}/bin/brightnessctl set 5%+";
+          "XF86MonBrightnessDown" = "exec ${pkgs.brightnessctl}/bin/brightnessctl set 5%-";
+        }
+      );
     };
   };
 
@@ -120,8 +132,20 @@
           block = "cpu";
           interval = 2;
         }
-        { block = "sound"; }
-        { block = "battery"; }
+      ]
+      # Desktop-only: CPU temperature and wired network throughput, in place
+      # of the laptop's battery readout.
+      ++ lib.optionals (!portable) [
+        {
+          block = "temperature";
+          interval = 5;
+          format = " $icon $average avg, $max max ";
+        }
+        { block = "net"; }
+      ]
+      ++ [ { block = "sound"; } ]
+      ++ lib.optional portable { block = "battery"; }
+      ++ [
         {
           block = "time";
           interval = 5;

system/modules/desktop.nix

@@ -0,0 +1,13 @@
+# Desktop (non-portable) NixOS hosts. Counterpart to ./laptop.nix: imports the
+# shared ./workstation.nix base and swaps the mobile Wi-Fi backend for wired
+# NetworkManager. A desktop host also sets `portable = false` in its host-table
+# entry (flake.nix), which drops the battery block and brightness keybindings
+# from the Sway bar -- see lyrathorpe/home/sway.nix.
+{ ... }:
+{
+  imports = [ ./workstation.nix ];
+
+  # Wired networking. NetworkManager handles DHCP/connections itself; do not
+  # combine with networking.wireless.* (laptop.nix) -- the two backends conflict.
+  networking.networkmanager.enable = true;
+}