refactor: Make hw definitions modules with mkIf guards

hw/nix-wsl.nix

@@ -7,16 +7,30 @@
 {
   lib,
   config,
-  inputs,
   ...
 }:
-{
-  imports = [
-    inputs.nixos-wsl.nixosModules.default
-    inputs.vscode-server.nixosModules.default
-  ];
 
-  # ========== Options ==========
+with lib;
+
+let
+  cfg = config.athenix.hw.nix-wsl;
+in
+{
+  options.athenix.hw.nix-wsl = mkOption {
+    type = types.submodule {
+      options = {
+        enable = mkOption {
+          type = types.bool;
+          default = false;
+          description = "Enable Windows Subsystem for Linux hardware configuration.";
+        };
+      };
+    };
+    default = { };
+    description = "WSL hardware type configuration.";
+  };
+
+  # WSL user option (at module level, not inside config)
   options.athenix.host.wsl.user = lib.mkOption {
     type = lib.types.str;
     default = "engr-ugaif";
@@ -29,7 +43,7 @@
     example = "alice";
   };
 
-  config = {
+  config = mkIf cfg.enable {
     # ========== WSL Configuration ==========
     wsl.enable = true;
     # Use forUser if set, otherwise fall back to wsl.user option
@@ -55,5 +69,8 @@
     # Provide dummy values for required options from boot.nix
     athenix.host.filesystem.device = "/dev/null";
     athenix.host.filesystem.swapSize = "0G";
+
+    # WSL doesn't use installer ISOs
+    athenix.host.buildMethods = lib.mkDefault [ ];
   };
 }