fix: expire stale call pushes

server/calls.go

@@ -37,6 +37,8 @@ const (
 	constCallEventHangUp = "hang-up"
 
 	// Message headers representing call states.
+	// Call is ringing.
+	constCallMsgStarted = "started"
 	// Call is established.
 	constCallMsgAccepted = "accepted"
 	// Previously establied call has successfully finished.
@@ -149,7 +151,7 @@ func normalizeCallInvite(head map[string]any, content any) (map[string]any, any,
 	for key, value := range head {
 		normalizedHead[key] = value
 	}
-	normalizedHead["webrtc"] = "started"
+	normalizedHead["webrtc"] = constCallMsgStarted
 	normalizedHead["x-im-type"] = "call"
 	if _, ok := normalizedHead["mime"]; !ok {
 		normalizedHead["mime"] = "application/json"