feat(tui): show tokens per second in the footer and sidebar

[atmikshetty]

Issue for this PR

Closes #21132

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

• This PR adds a functionality that allows users to see the tokens per second(TPS) of the current model they are using in the sidebar and the message footer.
• Streams the token when the responses are being generated.

How did you verify your code works?

• Tested it across multiple providers.
• Verified if the TPS is correct by checking the model cards on OpenRouter.

Screenshots / recordings

Recording of the few models I tried:

Screen.Recording.2026-04-06.at.3.48.33.AM.mov

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR

[github-actions]

The following comment was made by an LLM, it may be inaccurate:

Based on my search, I found potentially related PRs that address similar functionality:

Related PRs:

1. PR feat(tui): add tokens per second to response footer #12721 - "feat(tui): add tokens per second to response footer"

   • feat(tui): add tokens per second to response footer #12721
   • May be a previous or related attempt to add TPS display to the footer

2. PR feat(tui): show tokens per second in assistant message footer #14493 - "feat(tui): show tokens per second in assistant message footer"

   • feat(tui): show tokens per second in assistant message footer #14493
   • Directly addresses showing TPS in the footer, similar scope to current PR

3. PR feat(tui): add native status line template system #13885 - "feat(tui): add native status line template system"

   • feat(tui): add native status line template system #13885
   • May be related to the infrastructure for displaying tokens in the TUI

Recommendation: Check the status of PRs #12721 and #14493 to understand if they were merged, closed, or abandoned. The current PR (21133) may be building on, replacing, or fixing those previous attempts. Since the current PR closes issue #21132, verify that issue to understand the context.

[github-actions]

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