fix(vm): fix Plymouth, SDDM, and autologin for VM testing

- Add virtio_gpu to initrd.kernelModules for early graphics support in VMs.
- Add 'render' group to VM users to ensure GPU acceleration.
- Move autologin defaults to sddm.nix to ensure they are consistently applied.
- Ensure SDDM theme has better session detection for uwsm.

modules/system/sddm.nix

@@ -18,6 +18,11 @@ in
     theme = "nomarchy";
   };
 
+  services.displayManager.autoLogin = {
+    enable = lib.mkDefault true;
+    user = lib.mkDefault "nomarchy";
+  };
+
   environment.systemPackages = [ nomarchy-sddm-theme ];
 
   # Enable Hyprland system-level dependencies