Add pulsemixer

system/shared/multimedia/sound/default.nix

@@ -1,5 +1,6 @@
 {
   config,
+  pkgs,
   lib,
   ...
 }: let
@@ -12,6 +13,13 @@ in {
       enable = mkDefault false; # this just enables ALSA, which we don't really care abouyt
       mediaKeys.enable = true;
     };
+
+    environment.systemPackages = with pkgs; [
+      # TUI tool to manage sound devices & levels
+      # It's made for pulseaudio, but it will work with pipewire too since we 
+      # run a compatibility layer for pulse
+      pulsemixer
+    ];
   };
 }