Support for voice on linux-arm64

### Describe the feature or problem you'd like to solve

Support voice dictation for the copilot CLI on linux-arm64 platform.

### Proposed solution

I believe the Copilot CLI has a substantial user base using it on a Windows ARM machine that also primarily us it in WSL. Not supporting the linux-arm64 platform prevents them from using the voice feature.

### Example prompts or workflows

Relevant with any prompt one would want to dictate to the copilot CLI.

### Additional context

_No response_

未指定檔案、測試或進入點。先找出 Copilot CLI 的語音聽寫實作及其平台支援檢查，然後確認 linux-arm64 是如何處理的；當語音聽寫能在該平台上用於 prompts，且相關檢查通過時，即視為完成。

由索引模型根據 Issue 內容生成。