github-copilot: Use copilot cli for GitHub Copilot ACP

[imumesh18]

Use the latest copilot-cli acp instead of the language server one. Ref: https://github.blog/changelog/2026-01-28-acp-support-in-copilot-cli-is-now-in-public-preview/

[filipwiech]

I think it's a good idea to switch to the Copilot CLI, even the announcement blog post from Zed was mentioning it by name, so I was a little surprised to see the LSP being used instead:

The list of available agents in the registry already includes some of the best out there: Claude Code, Codex CLI, GitHub Copilot CLI, OpenCode, Gemini CLI, and many more.

Guess things are just brand new and moving fast. 😉

[ryan-carter-dot]

In registry readme, it mentions that

This registry only includes agents that support authentication. Agents must implement auth flows to be listed here.

The language server works to ask me for sign-in, but the copilot-cli seems not work for auth:

[ignatov]

Hey, the link was provided by github copilot team, asked them to commment

[nickzhums]

Hi @imumesh18 , as mentioned by @ryan-carter-dot , the registry requires agents that support authentication. Currently the CLI implementation does not support it, so using the CLS option should be the default one. In addition, this provides a more smooth experience. We will evaluate the implementation over time.