Add Support for Google's Imagen 4 Image Generation Model

Description:

Requested Feature: Please add Imagen 4 as an available model option for image generation tasks. This requires adding support for Google's Imagen 4 image generation model to the platform.

This is the tool in playground:

https://aistudio.google.com/prompts/new_image

Current Situation:

• The platform currently offers Gemini 2.0 Flash's native image generation capabilities

• However, Imagen 4 is a separate, more advanced image generation model from Google

• According to Google's documentation, Imagen 4 is accessible via API key

Why This Would Be Valuable:

• Imagen 4 offers enhanced image generation capabilities compared to the current options

• Users would benefit from having access to Google's latest dedicated image generation technology

• This would provide more choice and potentially better results for image creation workflows