Support HTTP proxy environment variables (http_proxy/https_proxy)

[femto]

Description

gws commands fail in environments requiring HTTP proxy (e.g., users in China who need proxy to access Google APIs).

Problem

The underlying yup-oauth2 and hyper HTTP clients don't respect standard proxy environment variables (http_proxy, https_proxy, ALL_PROXY).

Affected operations:

1. gws auth login - OAuth token exchange fails
2. All API calls - token refresh fails

Error message:

{
  "error": {
    "code": 401,
    "message": "Authentication failed: Failed to get token: Connection failure: Hyper error: client error (Connect): tcp connect error: Operation timed out (os error 60)",
    "reason": "authError"
  }
}

Environment

• macOS 14.x (Sonoma)
• gws 0.11.1
• Proxy: http://127.0.0.1:7890

Current Workaround

1. Manually exchange OAuth code using curl with proxy
2. Save credentials to ~/.config/gws/credentials.json
3. Use GOOGLE_WORKSPACE_CLI_TOKEN env var with manually refreshed access token

This is cumbersome as tokens expire every hour.

Suggested Fix

Option 1: Use reqwest with default features (includes proxy support):

# Cargo.toml - current
reqwest = { version = "0.12", features = ["json", "stream", "rustls-tls-native-roots"], default-features = false }

# Suggested - enable proxy support
reqwest = { version = "0.12", features = ["json", "stream", "rustls-tls-native-roots", "socks"] }

Option 2: Pass a custom hyper client with proxy support to yup-oauth2 using .with_hyper_client().

Option 3: Add explicit --proxy flag or GWS_PROXY / GWS_HTTPS_PROXY environment variable.

References

• reqwest proxy support: https://docs.rs/reqwest/latest/reqwest/struct.Proxy.html
• yup-oauth2 custom client support