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

contrib/systemd/sendspin-live-server.service

@@ -0,0 +1,17 @@
+[Unit]
+Description=Sendspin live audio streaming server
+After=pipewire.service network-online.target
+Wants=pipewire.service
+
+[Service]
+ExecStart=%h/.local/bin/sendspin-live-server \
+    --name %H \
+    --port 8927 \
+    --http-port 8080 \
+    --rate 48000 \
+    --channels 2
+Restart=on-failure
+RestartSec=5
+
+[Install]
+WantedBy=default.target