[Bug]: mcode 默认不走系统代理，导致 provider test 在仅有代理出口的机器上固定 10000ms 超时

Product or interface

CLI - interactive TUI

Version

0.4.12

Platform

Linux

OS version and architecture

openEuler 24.03 (LTS-SP1) aarch64

Issue area

Startup / install / update

Desktop log upload ID (optional)

No response

Steps to reproduce

这是一个代理不支持的常见问题，如果用国外 API BYOK 的方式就会触发问题。

我们机器仅有代理出口，所以同样触发了这个问题。但是这个问题并不只是在这里触发。MiniMax 给 FrontierHarness Eval 的 PR 中也提到了这一问题。这是一个普适性问题。

$ echo $http_proxy;echo $https_proxy;echo $socks_proxy;
http://127.0.0.1:7890
http://127.0.0.1:7890


$ mcode provider add \
  --name "ds4.1flash" \
  --base-url "https://api.deepseek.com/anthropic" \
  --api-format anthropic-messages \
  --model "deepseek-flash[1m]" \
  --use

$ mcode provider test provider-7b0fdd --model deepseek-flash
Provider test failed: Request timed out after 10000ms. Check the URL, API key, and model ID, then retry.

使用 MiniMax 给 FrontierHarness Eval 的 PR 中类似的 proxy-adapter 可以解决

// file: /tmp/mcode-proxy.cjs
const { EnvHttpProxyAgent, setGlobalDispatcher } = require('/tmp/mcode-proxy/node_modules/undici');
if (!process.env.HTTPS_PROXY && !process.env.HTTP_PROXY) {
  throw new Error('HTTP(S)_PROXY is required');
}
setGlobalDispatcher(new EnvHttpProxyAgent());

$ NODE_OPTIONS='--require=/tmp/mcode-proxy.cjs' \
  mcode provider test provider-851e29 --model deepseek-flash --json
{
  "success": true,
  "status": {
    "state": "available",
    "lastTestedAt": 1789782605854
  }
}

$ NODE_OPTIONS='--require=/tmp/mcode-proxy.cjs' \
  mcode exec --cwd /tmp --permission off --max-steps 2 --timeout 45s \
  --output-format json \
  --model custom_provider:provider-851e29/deepseek-flash \
  'Reply with exactly OK and do not inspect or modify any files.'

{"status":"succeeded","output":"OK","model":{"providerId":"custom_provider:provider-851e29","modelId":"deepseek-flash","protocol":"openai-completions"},"durationMs":1247}

Expected and actual behavior

期望行为：mcode 支持代理，避免代理情况下超时报错发生。

Redacted error summary

Screenshots

Before submitting

• I have searched existing issues.
• I have included my version and removed sensitive information.

Start with the mcode provider test and mcode exec entry points, reproducing the timeout on Linux with HTTP_PROXY and HTTPS_PROXY set. Trace how their outbound requests are made and compare the reported undici proxy-adapter behavior; done means provider tests and execution work through the configured proxy without the fixed 10000ms timeout.