Add reasoning settings for gpt-5 and o-series models

I'll take a stab at it

@marcus_johansson I've created an MR here, but this is no going to work with the chat completions api currently used, it gives:

Error invoking model response: Unknown parameter: 'reasoning'.

To make this work, we'd have to move to the Responses API, something like:

$response = $this->client->responses()->create([
    'model' => 'gpt-5',
    'reasoning' => [
        'effort' => 'medium',
        'summary' => 'auto',
    ],
    'input' => $payload, // same as the chat messages array
]);

I'm assuming that probably needs it's own ticket and testing. Marking this as NW for now.

ah, sorry - I've looked at the wrong API.

We should either switch over to the responses API or add a new operation type for it if its becomes standardized in other providers.

The correct API, is the Chat Completion: https://platform.openai.com/docs/api-reference/chat/create

This would be this variable only that we need to add then: https://platform.openai.com/docs/api-reference/chat/create#chat_create-r...

I'll update the issue.