Feat: Update Gemini model, and import module to absolute. update readme.

[Muhasix]

Idk. this version is what works for me.

1. The import using relative path is not works because what run is server.py not the package so I change it to remove the dot ( import .prompt -> import prompt)
2. update latest free image generator models by gemini.
3. the readme update is what works for me. idk how to explain.