Add GitHub Copilot CLI documentation to developer setup

[Copilot]

Documents the GitHub Copilot CLI (@github/copilot) as a recommended developer tool for terminal-based AI assistance.

Changes

CONTRIBUTING.md

• Added optional GitHub Copilot CLI setup section with installation, authentication, and usage examples

README.md

• Added "Recommended Developer Tools" section documenting Copilot CLI capabilities and common commands

Both sections include:

npm install -g @github/copilot
copilot auth
copilot suggest "run tests in watch mode"
copilot explain "git rebase -i HEAD~3"

Links to official documentation at https://githubnext.com/projects/copilot-cli

Original prompt

npm install -g @github/copilot

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[Copilot]

Pull Request Overview

This PR adds documentation for GitHub Copilot CLI as a recommended developer tool to help contributors with terminal-based AI assistance during development.

• Adds GitHub Copilot CLI installation and setup instructions
• Documents common use cases with command examples
• Provides links to official documentation

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
README.md	Adds "Recommended Developer Tools" section with GitHub Copilot CLI installation, usage examples, and benefits
CONTRIBUTING.md	Adds optional GitHub Copilot CLI setup section under development setup with authentication and usage guidance

[Copilot]

The link to GitHub Copilot CLI documentation may be outdated. Consider verifying this URL is still active and points to the official documentation. The CLI may now have official documentation under github.com/features/copilot or docs.github.com.

Suggested change

	Learn more: [GitHub Copilot CLI](https://githubnext.com/projects/copilot-cli)
	Learn more: [GitHub Copilot CLI Documentation](https://docs.github.com/en/copilot/copilot-cli)

[Copilot]

The link to GitHub Copilot CLI documentation may be outdated. Consider verifying this URL is still active and points to the official documentation. The CLI may now have official documentation under github.com/features/copilot or docs.github.com.

Suggested change

	For more information, visit: https://githubnext.com/projects/copilot-cli
	For more information, visit: https://docs.github.com/en/copilot/github-copilot-cli

[stevenschling13]

@copilot When merging it failed