Add Github Copilot as a provider.

[inayayousfi]

As someone who only pays for GitHub Copilot because of how worthy it is in terms of usage, I would gladly use lumen for generating commits etc. I think it should be doable because OpenCode managed to do it just like Zed.

[todaymare]

I’ve looked into this a bit. There are efforts around using Copilot outside of its official integrations, for example this repo:
https://github.com/ericc-ch/copilot-api

That said, I think the main blocker is that GitHub Copilot isn’t exposed as a proper public API with an API key like most other providers. It’s tightly coupled to GitHub’s auth flow and editor integrations, which makes clean third-party usage tricky and potentially fragile.

I think a better approach might be allowing users to run a local bridge/server that can respond to OpenAI's API.

Edit: I just noticed there’s already a PR that allows users to run their own local bridge/server. Once that’s merged, using GitHub Copilot should be as simple as running a local proxy (e.g. via the repo linked above). See #58.

[CanRau]

Came here to ask for the same.

Haven't looked into the code yet, tho I wanted to mention that Copilot SDK (https://github.com/github/copilot-sdk) might be useful?