[FEATURE]: show tokens / second

[IceWreck]

Feature hasn't been suggested before.

• [x] I have verified this feature I'm about to request hasn't been suggested before.

Describe the enhancement you want to request

Display current and average tokens/s for requests - will be ideal for comparing performance across different providers and models.

[github-actions[bot]]

This issue might be a duplicate of existing issues. Please check:

• #4577: Show the number of api requests made by opencode to the LLM in a session
• #4925: Display total cost for session

These issues are related to displaying performance metrics and detailed session information. Tokens/second metrics could be part of an expanded performance monitoring feature alongside these existing requests.

Feel free to ignore if your specific case differs from these.