Sandbox proxy settings use 127.0.0.1 instead of localhost in some cases

The sandbox is a restricted environment that Claude Code can run commands in. It routes their network traffic through a proxy, a local server that the traffic passes through. Claude Code tells the commands where the proxy is by setting environment variables. When an authentication value is set, those variables now give the proxy's address as 127.0.0.1 instead of localhost. This applies:

• Always for the HTTP proxy.
• For the SOCKS proxy only when it uses the same port as the HTTP proxy.

The variables affected are HTTP_PROXY, ALL_PROXY, GIT_SSH_COMMAND, DOCKER_HTTP_PROXY and CLOUDSDK_PROXY_ADDRESS.