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