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_

未指定文件、测试或入口点。首先定位 Copilot CLI 的语音听写实现及其平台支持检查，然后确定 linux-arm64 是如何处理的；当语音听写能在该平台上用于 prompts，且相关检查通过时，即视为完成。

由索引模型根据 Issue 内容生成。