feat: add PipeWire muter functionality and service files for Sendspin audio player

contrib/systemd/sendspin-client.service

@@ -0,0 +1,16 @@
+[Unit]
+Description=Sendspin audio player
+After=pipewire.service network-online.target
+Wants=pipewire.service
+
+[Service]
+ExecStart=%h/.local/bin/sendspin-client \
+    --server 192.168.1.100:8927 \
+    --name %H \
+    --device alsa_output.usb-Device-00.analog-stereo \
+    --volume 80
+Restart=on-failure
+RestartSec=5
+
+[Install]
+WantedBy=default.target