Guzzle: Proxy configuration not applied

[francescobianco]

Labels: feature, network, guzzle
Context: Guzzle 7.x

Description:
Openapi SDK internally creates its own HTTP client instead of using Guzzle's shared configuration. Proxy settings defined in Laravel or Guzzle global config are ignored.

Expected:
Add configuration parameter:
Openapi::configure(['proxy' => 'http://proxy.internal:8080']);

Impact:
Corporate environments with strict network routing cannot reach the API.