feat(chat): Clarify token usage in chat header (tooltip + task & project total)

[dataCenter430]

Related Issue

Closes #1441

Description

Improves the chat header token display so "Chat #0" is clearly understood as token usage and supports both task and project-level counts.

Changes

• Hover tooltip: The value next to "Chat" (e.g. # 0) now shows a tooltip on hover with the label "Token usage" and a short explanation.
• Task vs total: The tooltip shows this task token count and, when available, project total token count (e.g. "This task: 1,234 · Project total: 5,678").
• UX: Token number uses cursor-help and toLocaleString() for readable numbers.

Technical details

• HeaderBox: added optional totalTokens prop and wrapped token value in TooltipSimple.
• ChatBox: passes totalTokens from projectStore.getProjectTotalTokens(activeProjectId).
• i18n: new keys in all locales — chat.token-usage, chat.token-usage-this-task, chat.token-usage-project-total.

Testing Evidence (REQUIRED)

• I have included human-verified testing evidence in this PR.
• This PR includes frontend/UI changes, and I attached screenshot(s) or screen recording(s).
• No frontend/UI changes in this PR.

What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

Contribution Guidelines Acknowledgement

• I have read and agree to the Eigent Contribution Guideline

[dataCenter430]

16.03.2026_17.20.44_REC.mp4

[dataCenter430]

Hi, @Wendong-Fan @Pakchoioioi
Could you please review the PR when you have a chance?
Thank you. 🙏

[4pmtong]

Thanks @dataCenter430 for contribution. could @fengju0213 @a7m-1st help review it?

[fengju0213]

thanks @dataCenter430 the code logic looks good to me，but for user experience，shouldn we use a more intuitive way of expressing it?
cc @Douglasymlai @Pakchoioioi

[dataCenter430]

thanks @dataCenter430 the code logic looks good to me，but for user experience，shouldn we use a more intuitive way of expressing it? cc @Douglasymlai @Pakchoioioi

What do you prefer? Once you clarify it, I will implement it right away.

[Douglasymlai]

Hi @dataCenter430, yes — I think there are a few changes that would make it more user-friendly and easier to follow. I’ll put together a spec today and send it over tomorrow.

[dataCenter430]

Hi @dataCenter430, yes — I think there are a few changes that would make it more user-friendly and easier to follow. I’ll put together a spec today and send it over tomorrow.

Thanks for your review. Please do it. 👍
Once you clarify it, I will implement it perfectly.

[dataCenter430]

Hi, @Douglasymlai
Are there any updates for this feature?
Please tell me, so I can implement it.
Thank you

[Douglasymlai]

Hi @dataCenter430, sorry for the delay. I’ve put together a specification for a few changes that I think will improve the UX of these feature.

I’ve written the detailed plan in the markdown file, and included the related materials in the zip file. I usually share design files with developers in the community using a tool called Pencil. You can find the VS Code plugin: https://www.pencil.dev/. It connects easily with Claude Code or Codex, which should help with reviewing the UI design in more detail.

token-counting-design-spec.md
design material.zip

Example Outcome:

Thanks for your contribution. You can tag me for review after the change as been made. I will push the team for faster code formate review and merging to the main branch.

[dataCenter430]

Hi, @Douglasymlai thanks for the clarification.
So professional, okay, I got it.
Thank you

[dataCenter430]

Hi, @Douglasymlai
I've updated the UI as you wanted.

Also I've implemented the translations for that.
Really hope your review again.
Thank you.