[Fix] Approval controls disappear when user scrolls through chat

[zoomote]

​Created by Roomote. Follow up by mentioning @roomote, in the web UI, or in Discord.

What changed

• Keep pending approval controls visible beside a compact scroll-to-bottom action while users browse earlier chat output.
• Prioritize approvals over the optional checkpoint shortcut and truncate long localized labels safely in narrow sidebars.
• Add regression coverage that reproduces a scrolled child task receiving finishTask approval, including a prior checkpoint state.

Why this change was made

Scrolling previously replaced the entire action row with navigation controls. A child task waiting for completion approval therefore appeared stuck because the only control that could return to its parent was no longer rendered.

Closes #1447.

Impact

Users can approve subtask completion and other blocking actions without first changing their chat scroll position. The regression was developed test-first and the full repository suite passes. A post-fix extension screenshot is not included because this task's approved proof browser exposes only the documentation site, not the VS Code Extension Host surface.

Related PRs

• Documentation: [Docs] Explain approval controls while browsing chat history Zoo-Code-Docs#53

[codecov]

Codecov Report

❌ Patch coverage is 73.91304% with 6 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
webview-ui/src/components/chat/ChatView.tsx	73.91%	1 Missing and 5 partials ⚠️

📢 Thoughts on this report? Let us know!

[github-actions]

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