fix(agent): keep agent chat sidebar scroll container shrinkable

[euvre]

Problem

In the agent canvas debug chat sidebar, the streaming answer area could fail to stay anchored to the bottom because the message-list scroll container (web/src/pages/agent/chat/box.tsx) was a flex-1 overflow-auto flex item without an explicit min-h-0. Both sibling chat containers already carry min-h-0 on the same pattern:

• web/src/pages/next-chats/chat/chat-box/single-chat-box.tsx (line 86)
• web/src/pages/agent/explore/components/session-chat.tsx (line 122)

Change

Add min-h-0 to the scroll container class list in box.tsx, so the flex item is explicitly shrinkable instead of relying on overflow:auto zeroing its automatic minimum size, keeping the auto-scroll-to-bottom behavior stable regardless of how ancestors size the flex column.

Verification

Ran the agent debug chat drawer against a ~6k-char streaming answer and sampled the scroll container every second: scrollTop + clientHeight >= scrollHeight - 25 held for every sample (atBottom true), computed min-height: 0px, and the drawer layout is unchanged.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 0fa6b906-212f-4ec2-b775-e232711a08bc

📥 Commits

Reviewing files that changed from the base of the PR and between 423c848 and 2925bd7.

📒 Files selected for processing (1)

• web/src/pages/agent/chat/box.tsx

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📝 Walkthrough

Walkthrough

The chat message container now uses min-h-0 in its flex layout. Existing scrolling behavior and ref assignment remain unchanged.

Changes

Chat layout

Layer / File(s)	Summary
Message container sizing web/src/pages/agent/chat/box.tsx	The message container adds min-h-0 while retaining its scrollable flex behavior and ref assignment.

Estimated code review effort: 1 (Trivial) | ~2 minutes

Mergeability Score: ⚪ Minimal · up to 2925b

This change makes the chat scroll container explicitly shrinkable to preserve streaming auto-scroll behavior without changing the drawer layout; no actionable merge-blocking risk remains.

Suggested reviewers: dcc123456

Poem

A bunny nudges the chat box low,
So messages can scroll and flow.
With min-h-0 in place,
Flex space finds its place.
Hop, hop—smooth chats now grow!

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description check	✅ Passed	The description clearly explains the problem, change, and verification, but it uses different headings from the repository template.
Title check	✅ Passed	The title clearly and concisely describes the fix to keep the agent chat sidebar scroll container shrinkable.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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[wangq8]

Reviewed. Adding min-h-0 to the flex-1 overflow-auto scroll container is correct and matches the sibling chat containers (single-chat-box.tsx, session-chat.tsx). This is the canonical fix for the flex-item automatic-minimum-size issue that breaks bottom-anchored auto-scroll. LGTM.