add polkit and attempt to autostart swaybg in niri

system/services/swaybg.nix

@@ -0,0 +1,16 @@
+{config, pkgs, ...}:
+{
+  systemd.user.services.swaybg-autoset = {
+    enable = true;
+    description = "start swaybg on login";
+    after = ["waybar.service"];
+    requires = ["network-online.target"];
+    before = ["multi-user.target"];
+    wantedBy = ["multi-user.target"];
+    serviceConfig = {
+      ExecStart = "swaybg -i ~/Downloads/wp.jpg";
+      User = "autumn";
+      Group = "users";
+    };
+  };
+}