Mouse right-click paste not working in Copilot CLI

## Description

Right-click context menu paste does not work in the Copilot CLI terminal input. Users cannot paste text using mouse right-click.

## Steps to Reproduce

1. Copy some text to clipboard
2. In the Copilot CLI input prompt, right-click to paste
3. Nothing happens — text is not pasted

## Expected Behavior

Right-click paste should insert clipboard contents into the CLI input, consistent with standard terminal behavior.

## Environment

- OS: Linux (RHEL/CentOS)
- Copilot CLI version: 1.0.10