PR for Clipboard Hook Leak (clipboard_44)

This PR addresses the memory leak identified in leak-report/guaranteed/clipboard_44.md.

Description

The useCopyToClipboard hook in webview-ui/src/utils/clipboard.ts uses a setTimeout to manage feedback visibility. This timeout is not cleared when the component unmounts, leading to potential React state update warnings on unmounted components.

This patch implements the suggested fix from the leak report, using useRef to store the timeout ID and useEffect to ensure the timeout is cleared on component unmount or when feedbackDuration changes.

Related Bug Report

#4227

Changes

• Modified webview-ui/src/utils/clipboard.ts to correctly manage the setTimeout lifecycle.
  • Added useEffect and useRef.
  • Ensured clearTimeout is called on unmount and before setting a new timeout.
• Add/update unit tests for useCopyToClipboard.

How to Test

1. Integrate the useCopyToClipboard hook into a test component.
2. Call copyWithFeedback.
3. Unmount the test component before feedbackDuration (e.g., 2 seconds) expires.
4. Verify that no React warnings about state updates on unmounted components appear in the console.