Add content moderation support via OpenAI moderations endpoint

[ahmadmayahi]

• Add content moderation support via OpenAI's /moderations endpoint
• Support for all 13 moderation categories with flagged status and confidence scores

use Laravel\Ai\Moderation;

$response = Moderation::check('I want to hurt someone');

 // true/false
$response->flagged;                      

// all categories
$response->categories;

// only flagged ones
$response->flaggedCategories(); 

// specific category
$response->category('violence');