Add github.com-cli feature

[Copilot]

Adds a new devcontainer feature that installs the GitHub CLI (gh) binary via the official cli.github.com/packages apt repository. Based on the implementation drafted in PR #104.

New files

• src/github.com-cli/devcontainer-feature.json — Feature metadata; ID follows repo's domain-based naming convention (e.g. cloudflare.com-warp-cli)
• src/github.com-cli/install.sh — Adds the GitHub CLI GPG key + apt source, forces apt-get update to pick up the new source, installs gh
• src/github.com-cli/README.md — Auto-generated-style documentation
• test/github.com-cli/test.sh — Smoke test: gh --version | grep 'gh version'

CI

Added github.com-cli to both test-autogenerated and test-scenarios matrices in .github/workflows/test.yaml.

Usage

"features": {
    "ghcr.io/devcontainer-community/devcontainer-features/github.com-cli:1": {}
}

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Add github.com-cli feature</issue_title>
<issue_description>build on implementation in #104 </issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Add github.com-cli feature #123

---

📱 Kick off Copilot coding agent tasks wherever you are with GitHub Mobile, available on iOS and Android.