github/CopilotForXcode ? reverse-engineered prompt

Build me a macOS app for Xcode that works like GitHub Copilot for Swift, Objective C, and iOS or macOS development.

I want it to show smart code completions while I type, let me open a chat panel inside Xcode for asking coding questions, and offer an agent mode that can read my project, suggest edits across multiple files, create new files, and run simple terminal commands when needed. It should also support code review style help, next edit suggestions, and a way to sign in with GitHub so the assistant can work on my account.

Please make it feel like a real Xcode companion app with the right permissions, background connection, and source editor extension so it shows up under Xcode’s Editor menu. Include a simple settings window for signing in, checking for updates, and turning features on or off. If anything depends on current GitHub or Xcode behavior, look up the latest docs online before you build it.