It is possible to create a Roku channel that uses the Twitter API.
However, Twitter's API and the degree of access provided is continuing to evolve over time as explained in this article:https://www.theverge.com/2018/5/16/17362138/twitter-api-third-party-apps-changes-explained
In your view, what exactly would a Twitter client on Roku do?
You would want to watch tweets for a specific search term that is updated once per minute?
You would want to be able to login and check your friends list?
How complex dd you see this being?