Clipboard API paste does not work in contenteditable

Phenomenon

When using the Clipboard API (navigator.clipboard.readText() or navigator.clipboard.read()) to programmatically paste content into a contenteditable region, the paste operation may fail or not work as expected.

Reproduction example

1. Create a contenteditable div.
2. Copy some text to the clipboard.
3. Use JavaScript to read from clipboard: await navigator.clipboard.readText().
4. Try to insert the text into the contenteditable.
5. Observe whether the paste works correctly.

Observed behavior

• In Chrome on macOS, Clipboard API operations may fail in contenteditable contexts.
• Permission errors may occur.
• The paste may not trigger expected events or behaviors.

Expected behavior

• Clipboard API should work reliably in contenteditable contexts.
• Permissions should be handled correctly.
• Paste operations should trigger appropriate events.