Thanks for asking me to work on this. I will get started on it and keep this PR's description up to date as I form a plan and make progress.

This pull request was created as a result of the following prompt from Copilot chat.

Add macOS-specific installation instructions to the README.md file.

Currently, the README only shows the npm installation method. Many macOS users prefer using Homebrew for package management. Please add a new subsection under the "Installation" section that includes:

1. A note that the tool can be installed via Homebrew on macOS
2. The Homebrew installation command
3. Keep the existing npm installation instructions as an alternative method

The new section should be added after line 40 (after "### Installation") and before line 42 (before "Install globally with npm:").

Suggested content structure:

• Add a subheading for npm installation
• Add a subheading for Homebrew installation (macOS)
• Include the command: brew install github/gh/copilot-cli (or the appropriate Homebrew formula if different)
• Make it clear that both methods are valid options

Please verify the correct Homebrew formula name by checking if github/gh tap exists or if there's an official Homebrew formula available. If Homebrew installation is not yet available, add instructions for installing via npm specifically for macOS users, and mention any macOS-specific considerations like ensuring Xcode Command Line Tools are installed.

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