fix wpctl volume pinning

configuration.nix

@@ -173,11 +173,13 @@ in
       Type = "oneshot";
     };
     script = ''
-      # Wait until WirePlumber exposes at least one sink
+      # Wait until WirePlumber exposes at least one sink.
+      # `wpctl list` output is tab-separated: ID, name, media/object type,
+      # then `*` if the node is the current default. `cut -f1` grabs the ID.
       sinks=""
       for i in {1..30}; do
         sinks=$(${pkgs.wireplumber}/bin/wpctl list audio sinks 2>/dev/null \
-          | ${pkgs.gnused}/bin/sed -nE 's/^.*[^0-9]([0-9]+)\. .*$/\1/p')
+          | ${pkgs.coreutils}/bin/cut -f1)
         if [ -n "$sinks" ]; then
           break
         fi
@@ -193,6 +195,10 @@ in
       # Fallback in case the sink list came up empty
       ${pkgs.wireplumber}/bin/wpctl set-volume @DEFAULT_AUDIO_SINK@ 1.0 2>/dev/null || true
       ${pkgs.wireplumber}/bin/wpctl set-mute @DEFAULT_AUDIO_SINK@ 0 2>/dev/null || true
+
+      # Persist 100% as WirePlumber's default for any brand-new sink so it
+      # comes up at full volume even before this service runs on next boot.
+      ${pkgs.wireplumber}/bin/wpctl settings device.routes.default-sink-volume 1.0 --save 2>/dev/null || true
     '';
   };