vm: add aarch64 UTM test target + cleanup pi/qmd placement

- nixosConfigurations.vm: minimal NixOS for aarch64 UTM testing
  - modules/vm.nix: network, SSH, user, no display manager
  - imports shared + wgu home configs, no desktop/Hyprland
- Moved pi/qmd from sscoble.nix → desktop.nix (clean separation)

flake.nix

@@ -82,6 +82,27 @@
       ];
     };
 
+    # === VM: minimal NixOS for testing (aarch64, UTM) ===
+    nixosConfigurations.vm = nixpkgs.lib.nixosSystem {
+      system = "aarch64-linux";
+      modules = [
+        home-manager.nixosModules.home-manager
+        ./modules/vm.nix
+        {
+          home-manager = {
+            useGlobalPkgs = true;
+            useUserPackages = true;
+            users.sscoble = {
+              imports = [
+                ./home/sscoble.nix
+                ./home/wgu.nix
+              ];
+            };
+          };
+        }
+      ];
+    };
+
     # === macOS: home-manager standalone (no desktop, no Hyprland) ===
     homeConfigurations.sscoble = home-manager.lib.homeManagerConfiguration {
       pkgs = nixpkgs.legacyPackages.${darwinSystem};