This PR adds the token count to the active thread view. It doesn't behaves quite like Assistant 1 where it updates as you type, though; it updates after you submit the message. <img src="https://github.com/user-attachments/assets/82d2a180-554a-43ee-b776-3743359b609b" width="700" /> --- Release Notes: - agent: Add token count in the thread view --------- Co-authored-by: Agus Zubiaga <hi@aguz.me>