Feature Request

Problem

Currently, the Laravel facade doesn't provide a way to set custom headers for individual requests. Headers can only be set globally when the client is instantiated in the ServiceProvider. This limitation makes it difficult to add request-specific headers for solutions like AI Gateway from Cloudflare: https://developers.cloudflare.com/ai-gateway/configuration/caching/#per-request-caching

Proposed Solution

Add a withHeaders() method that can be chained before accessing resources like chat(), completions(), etc.

Ideal API:

use OpenAI\Laravel\Facades\OpenAI;

$result = OpenAI::withHeaders([
    'x-custom-header' => 'custom-value',
    'cf-aig-skip-cache' => true,
])
->chat()
->create([
    'model' => 'o3',
    'messages' => [
        ['role' => 'user', 'content' => 'Hello!'],
    ],
]);

Benefits

• Enables request-specific headers without creating multiple client instances
• Maintains the clean facade API while adding flexibility
• Useful for logging, tracing, authentication, and other middleware scenarios

Current Workaround

Users currently need to create separate client instances with custom HTTP clients, which is verbose and doesn't integrate well with the Laravel facade pattern.