[BUG] VS Code extension: "The user modified your proposed changes" notification never appears

What's Wrong?

When using the VS Code extension, if I modify the proposed diff before accepting it, Claude never receives the "The user modified your proposed changes before accepting them" notification. Claude always treats the edit as if the original proposal was accepted unchanged.

What Should Happen?

Same behavior as CLI mode: when I modify the proposed changes in the diff editor before accepting, Claude should be notified about the modification.

In CLI mode this works correctly — after accepting a modified diff, the tool result contains:

The file X has been updated successfully.  The user modified your proposed changes before accepting them.

Error Messages/Logs

No errors. The file is updated correctly, but the notification is simply absent.

Steps to Reproduce

1. Open Claude Code in VS Code extension mode
2. Ask Claude to edit a file (e.g. "add a line to this file")
3. When the diff editor opens, modify the proposed changes on the right side (type something extra)
4. Click Accept in Editor view tab
5. Observe Claude's next message — it doesn't acknowledge the modification

For comparison, do the same in CLI mode (without the VS Code extension) — the notification appears correctly.

Additional Information

The behavior difference between CLI and VS Code extension modes suggests the issue is in how the extension communicates the accepted diff content back to Claude.