fix: support HTTPS proxy agent for REST requests

[HunterXuanBot]

Bug Description

binance-cli currently fails to access HTTPS Binance REST endpoints through a standard HTTP forward proxy set via environment variables such as HTTPS_PROXY.

In restricted-location environments, users often need to route Binance API calls through an allowed proxy. With the current CLI, proxied HTTPS requests can fail with:

Request failed after 3 retries
AxiosError: timeout of 1000ms exceeded

Root Cause

The CLI reads API credentials/profile configuration but does not translate standard proxy environment variables into a proper HTTPS CONNECT agent for the REST connectors.

Axios' plain proxy configuration is not reliable for this HTTPS-over-HTTP proxy use case. The request should disable Axios proxy handling and use an HTTPS proxy agent instead.

Fix

• Add https-proxy-agent as a runtime dependency.
• Read proxy URLs from existing standard environment variables:
  • HTTPS_PROXY / https_proxy
  • HTTP_PROXY / http_proxy
• When a proxy URL is present, configure REST clients with:
  • proxy: false
  • httpsAgent: new HttpsProxyAgent(proxyUrl)

How to Verify

1. Run without a proxy from a restricted-location host and confirm Binance returns the existing restricted-location response.
2. Run through an HTTP proxy that supports CONNECT:

HTTPS_PROXY=http://proxy.example:3128 \
binance-cli spot ticker-price --symbol BNBUSDT --profile <profile>

3. Verify signed endpoints still work through the proxy:

HTTPS_PROXY=http://proxy.example:3128 \
binance-cli wallet get-api-key-permission --profile <profile>

Test Plan

• npm run build
• npm run typecheck
• npm run lint
• Manual verification of a public REST endpoint through an HTTP CONNECT proxy
• Manual verification of a signed wallet endpoint through an HTTP CONNECT proxy

Risk Assessment

Low — this only changes behavior when standard proxy environment variables are set. Existing users without those variables keep the current behavior.