feat: add redis cache and fanout support

server/calls.go

@@ -86,7 +86,7 @@ type videoCall struct {
 	// Call participants (session sid -> callPartyData).
 	parties map[string]callPartyData
 	// Call message seq ID.
-	seq int
+	seq int64
 	// Call message content.
 	content any
 	// Call message content mime type.
@@ -300,7 +300,7 @@ func (call *videoCall) messageHead(head map[string]any, newState string, duratio
 		head = map[string]any{}
 	}
 
-	head["replace"] = ":" + strconv.Itoa(call.seq)
+	head["replace"] = ":" + strconv.FormatInt(call.seq, 10)
 	head["webrtc"] = newState
 
 	if duration > 0 {