add notification toggle

modules/home/waybar/modules/notifications.nix

@@ -0,0 +1,27 @@
+{ pkgs, lib, ... }:
+
+let
+  inherit (lib) mkDefault;
+  dunst = "${pkgs.dunst}/bin/dunstctl";
+in
+{
+  format = mkDefault "{icon}";
+  format-icons = {
+    unmuted = mkDefault "";
+    muted = mkDefault "";
+  };
+  return-type = mkDefault "json";
+  exec = mkDefault (
+    pkgs.writeShellScript "notifications" ''
+      is_paused=$(${dunst} is-paused)
+      if [ "$is_paused" = "true" ]; then
+        echo '{"alt": "muted", "class": "muted"}'
+      else
+        echo '{"alt": "unmuted", "class": "unmuted"}'
+      fi
+    ''
+  );
+  on-click = mkDefault "dunst-toggle";
+  interval = mkDefault "once";
+  signal = mkDefault 12;
+}