Change word to "credits" on usage meter

The usage meter is now showing how many credits a user has left for the month. During the redesign it got changed to "tokens" which is a bit confusing. I think we should change it back to "credits".

<img width="283" height="75" alt="Image" src="https://github.com/user-attachments/assets/201996f5-30c1-4ff0-a4c2-00acfea32d44" />