feat: Integrate Github Copilot subscriptions in cli

[liangfung]

Is your feature request related to a problem? Please describe.

Currently, Pochi does not integrate with GitHub Copilot subscriptions, which limits its capabilities for users who rely on Copilot for code completion and suggestions. This integration is essential for providing a seamless experience and leveraging the full potential of both tools.

Describe the solution you'd like

I would like to see an integration that allows Pochi to use GitHub Copilot subscriptions. This would involve:

1. Authentication: Securely authenticating with GitHub to verify an active Copilot subscription.
2. Model Access: Accessing Copilot's models to provide code completions and suggestions within the Pochi environment.
3. Seamless Integration: Ensuring that the integration is seamless and does not disrupt the existing user workflow.

This is related to the work being done in issue #62: #62

Additional context

This feature would significantly enhance Pochi's value proposition by combining its powerful features with Copilot's industry-leading code completion capabilities.

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🤖 Generated with Pochi

[liangfung]

• Completed the GitHub Copilot authentication process.
• Make a successful API call to Copilot's LLM.