[BUG] lower case of https_proxy / http_proxy / no_proxy environmental variables should be supported in addition to their uppercase variants

Environment

• Platform (select one):
• [X] Anthropic API
• Claude CLI version: 1.0.15 (Claude Code)
• Operating System: Ubuntu 24.04.2 LTS
• Terminal: iTerm 2

Bug Description

https_proxy / http_proxy / no_proxy environmental variables should be supported in additional to their uppercase variants. This is standard in the majority of the unix tools already.

https://www.gnu.org/software/wget/manual/html_node/Proxies.html
https://curl.se/docs/manpage.html#ENVIRONMENT

The environment variables can be specified in lower case or upper case. The lower case version has precedence. "http_proxy" is an exception as it is only available in lower case.

Steps to Reproduce

https_proxy=http://trusted-egress-proxy.service:8080 ./claude

Expected Behavior

Successfully login

Actual Behavior

Failed to connect to api.anthropic.com: "https://api.anthropic.com/api/hello" is not a function (near '...path${protocol2}//${host3}${this[kUseDefaultPort] ? "" : ":" + this[kPort]}...')

Additional Context

Theres probably somewhere in the code that needs

process.env.https_proxy || process.env.HTTPS_PROXY