feat: Auto-scroll to latest logs for worker sub-tasks

[spider-yamet]

Related Issue

Closes #1315

Description

Implements auto-scroll for the worker sub-task log panel in the Workflow view so the latest toolkit logs stay visible without manual scrolling.

Changes:

• src/components/WorkFlow/node.tsx: When the workflow node is expanded and a task is selected, the right-hand log panel (which shows selectedTask.toolkits) now scrolls to the bottom when:
  • New toolkit entries are added, or
  • The last toolkit’s message is updated (e.g. streaming).
• Auto-scroll only runs when the user is already near the bottom of the log (~60px threshold). If the user scrolls up to read history, the view does not jump back to the bottom until they scroll near the bottom again.
• When switching the selected task or opening the log panel, the view scrolls to the bottom so the latest logs are shown.

This addresses the behavior requested in #1315 (auto-scroll so latest logs are always visible).

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.

(Attach a short screen recording or screenshots showing: workflow node expanded, task running with toolkit logs, log panel auto-scrolling to the latest entry as new logs appear; optionally, scrolling up and confirming it does not override until you scroll back near the bottom.)

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

[bytecii]

Can you make a screenshot in the description? Thanks.

[spider-yamet]

22.02.2026_17.31.15_REC.mp4

Hi, I have added screen recording, I added test button for mock testing. (not mentioned on PR, only for test)
Please check, @bytecii @Wendong-Fan

[spider-yamet]

could you please review, @bytecii @Wendong-Fan

[spider-yamet]

@bytecii @Wendong-Fan could you please review this PR?

[spider-yamet]

@bytecii I added screenshot for this update, please check once you are available.

[spider-yamet]

@bytecii @Wendong-Fan I see this PR remains opening for several weeks.
Could you please check once you are available?

Regards

[spider-yamet]

Could you let me know your plan, @bytecii @fengju0213 @Wendong-Fan ?

Regards

[Wendong-Fan]

thanks @spider-yamet 's contribution and sorry for the late review, left some comments below

[Wendong-Fan]

wasAtBottomRef.current is reset to true on each toolkit update, so the log panel still jumps to the bottom even if the user has scrolled up to read older logs? i think we should respect users' action

[Wendong-Fan]

The effect depends on useMemo([selectedTask?.toolkits]), but toolkits is mutated in place in chatStore, so some log/message updates may not retrigger auto-scroll

[spider-yamet]

@Wendong-Fan Thanks for your feedback, I updated code by following your feedback.

Functional behavior diff

Before

• Auto-scroll effect ran when:
  • isExpanded changed
  • selectedTask?.id changed
  • selectedTask?.toolkits?.length changed
  • lastToolkitMessage changed
• The effect forcibly set:
  • wasAtBottomRef.current = true
• Result:
  • Even if the user scrolled up, the next toolkit update could jump the panel back to bottom.
  • Some updates were not detected reliably when toolkits was mutated in place.

After

• Auto-scroll effect now uses a computed toolkitChangeKey:
  • taskId
  • toolkit length
  • last toolkit id
  • last toolkit status
  • last toolkit message
• The effect does not reset wasAtBottomRef.
• Result:
  • User scroll position is respected (no forced jump to bottom).
  • In-place toolkit mutations are more reliably detected, so auto-scroll triggers when meaningful toolkit data changes.

I tested functionality on my end.

[spider-yamet]

@Wendong-Fan Could you please review current update? :)

[Wendong-Fan]

thanks @spider-yamet , added some enhance in ce13c79, now LGTM