Authentication fails on WSL despite correct environment and localhost networking

從 :Copilot setup 背後的實作以及導致 Vim 顯示 "Waiting..." 的驗證回呼開始。使用回報的 Ubuntu、Vim 和 Node 版本在 WSL 2 上重現此流程，並將 localhost 測試詳細資訊作為背景。瀏覽器驗證完成、回呼抵達 Vim 且 Copilot 回報已驗證狀態，即表示完成。

The Copilot for Vim extension fails to complete the authentication process on my WSL (Ubuntu 24.04) setup. The authentication is successful in the browser, but the callback to Vim never completes, and Vim remains stuck on the "Waiting..." message.

I have performed this troubleshooting and can confirm the issue is not with my local environment.

Symptom:

Running :Copilot setup provides a code.
Authenticating in a browser (running inside WSL) succeeds with the "Congratulations, you're all set!" message.
Vim remains stuck on "Waiting (could take up to 5 seconds)" and never receives the authentication confirmation.
Troubleshooting Steps Performed:

Plugin Version: The issue occurs on both the latest version and after downgrading to v1.41.0.
WSL-Native Browsers: The issue occurs with multiple browsers installed and running directly within WSL, including:
Firefox (installed via Snap)
Google Chrome (non-Snap Deb version)
Firewall: Confirmed that ufw is not installed or active.
Localhost Networking Test: I have confirmed that basic localhost communication within WSL is working perfectly. A Python http.server can be successfully reached from curl via localhost.
This testing suggests the issue is a bug within the Copilot agent's internal web server or its callback handling mechanism within a WSL environment.

My Environment:

OS: Windows 11
WSL Version: WSL 2
Linux Distribution: Ubuntu 24.04 LTS
Vim Version: 9.1
Node Version (in wsl): 22.16.0
Copilot Status after hang and restart: Copilot: Not authenticated. Invoke :Copilot setup (process then repeats)

(Above is AI generated)