feat: refactor client methods

- change `ProcessServerMessages` to use receiver instead of parameter
- update `Disconnect` method to use receiver for better encapsulation
- move `Client` definition to `connect.go`

🤖

cmd/client/main.go

@@ -49,8 +49,8 @@ func Start() {
 	client.Password = config.Password
 
 	channel := make(chan GoTomato.ServerMessage)
-	go websocket.ProcessServerMessages(client, channel)
+	go client.ProcessServerMessages(channel)
 	frontend.UpdateLoop(client, config, channel)
 
-	websocket.Disconnect(client)
+	client.Disconnect()
 }