module-rtp-sap: support PTP management protocol

Request current clock sync status to know the grandmaster identity for SAP announcements

src/daemon/pipewire-aes67.conf.in

@@ -68,6 +68,7 @@ context.modules = [
             sap.port = 9875
             net.ttl = 32
             net.loop = false
+            ptp.management-socket = "/var/run/ptp4lro"
 
             stream.rules = [
                 {
@@ -116,7 +117,6 @@ context.modules = [
             # please change this, especially for multiple streams
             sess.name = "PipeWire RTP stream"
             sess.media = "audio"
-            ### please select the PTP grandmaster ID here
             sess.ts-refclk = "ptp=traceable"
             sess.ts-offset = 0
             sess.latency.msec = 3
@@ -135,6 +135,7 @@ context.modules = [
                 node.always-process = true
                 node.group = pipewire.ptp0
                 rtp.ntp = 0
+                rtp.fetch-ts-refclk = true
             }
         }
     },