Voice mode dowload fails with corporate proxy ENOTFOUND

### Describe the bug

[apply-foundry-proxy-patch.js](https://github.com/user-attachments/files/29883462/apply-foundry-proxy-patch.js)

The download of the voice mode inference runtime failed with "Error: Failed to download Microsoft.AI.Foundry.Local.Core 1.2.3 from any configured feed (api.nuget.org, pkgs.dev.azure.com): getaddrinfo ENOTFOUND pkgs.dev.azure.com" behind the corporate proxy despite proper setup of Px and env vars.

Root cause: the vendored `foundry-local-sdk/script/install-utils.cjs` downloads NuGet packages using a bare `https.get()` call. Node's built-in `http`/`https` modules never read HTTP_PROXY/HTTPS_PROXY env vars on their own (unlike curl or most other tools), so the request bypasses the proxy entirely and fails to resolve DNS/connect directly.

Additionally, `copilot.exe` is a compiled Node "Single Executable Application" (SEA) binary that silently ignores NODE_OPTIONS, so the usual `-r some-proxy-shim.js` / `global-agent` tricks do NOT work here — the shim never loads inside the actual copilot process or its worker threads.

See attached file for temporary workaround.

### Affected version

GitHub Copilot CLI 1.0.70

### Steps to reproduce the behavior

Enter /voice on
Confirm download of model
Observe download failure

### Expected behavior

Setup behind corporate proxy is supported.

### Additional context

_No response_

從 vendored foundry-local-sdk/script/install-utils.cjs 開始，檢查隨附的 apply-foundry-proxy-patch.js workaround，然後使用回報的 Proxy 環境重現 /voice 下載。完成的標準是：不依賴 NODE_OPTIONS，即可透過已設定的企業 Proxy 成功下載 Microsoft.AI.Foundry.Local.Core package。

由索引模型根據 Issue 內容生成。