feat(nix): add salut service and nm-applet

nix/home-manager/programs/salut.nix

@@ -4,14 +4,39 @@
   lib,
   packages',
   ...
-}: {
+}:
+# useful testing command:
+# for i in `seq 0 10`; do nix shell nixpkgs#libnotify --command notify-send notifiiiiiii "$i"; sleep 1; done
+
+let
+  inherit (import ../lib.nix {}) mkSimpleTrayService;
+in
+{
   home.packages = [
     packages'.salut
   ];
 
-  home.file.".config/salut/config.ini" = {
+  xdg.configFile."salut/config.ini" = {
     enable = true;
     text = ''
+      [notifications]
+      timeout = 5
+
+      [window]
+      auto-hide = true
+      anchor = bottom
+
+      [mode]
+      single = true
+      do-not-disturb = false
+
+      [style]
+      preference = dark
     '';
+    onChange = "${pkgs.systemd}/bin/systemctl --user restart salut";
+  };
+
+  systemd.user.services.salut = mkSimpleTrayService {
+    execStart = "${packages'.salut}/bin/salut";
   };
 }