Add gpt-image-1-mini to replace deprecated dalle-2 and dalle-3 models.

[AndraxDev]

As noted in official OpenAI deprecation email.

As part of our continuous upgrade process, we are deprecating the following models on May 12, 2026:

• Dall-e-2
• Dall-e-3

Ahead of the shutdown timeline, we encourage you to explore gpt-image-1, our latest flagship models.

Thanks for building with OpenAI. If you have any questions about model migration, feel free to reach out on the OpenAI Developer Forum.