allow wsl users to be changed with options

hosts/types/nix-wsl.nix

@@ -2,9 +2,16 @@
 [
   inputs.nixos-wsl.nixosModules.default
   inputs.vscode-server.nixosModules.default
-  ({ lib, ... }: {
+  ({ lib, config, ... }: {
+    options.host.wsl.user = lib.mkOption {
+      type = lib.types.str;
+      default = "engr-ugaif";
+      description = "The default user to log in as in WSL.";
+    };
+
+    config = {
       wsl.enable = true;
-    wsl.defaultUser = "engr-ugaif";
+      wsl.defaultUser = config.host.wsl.user;
       
       # Enable the headless software profile
       modules.sw.enable = true;
@@ -24,5 +31,6 @@
       # Provide dummy values for required options from boot.nix
       host.filesystem.device = "/dev/null";
       host.filesystem.swapSize = "0G";
+    };
   })
 ]