Add Flux.2 Klein Inpaint pipeline

[Natans8]

The currently implemented Flux2KleinPipeline supports txt2img and img2img, however there isn't an option to pass a mask image to it.

A Flux2KleinInpaintPipeline would be most useful to address this case and allow to use the model to its full extent.

[ansonphong]

Yes having masked inpainting is critical for my application. There is no way to implement Flux2 in my app without this feature. Please add it, thanks!

[adi776borate]

Hi! I’d like to take this up.
I’ve reviewed the Flux.2 Klein pipeline and have started drafting the inpainting pipeline. For implementation details, I’ll be using FluxInpaintPipeline as my primary reference.

[asomoza]

thanks and please go ahead, but I recommend you use src/diffusers/pipelines/flux/pipeline_flux_kontext_inpaint.py as a guide since the klein models are also edit models, if using flux inpaint works for you, that's fine too.

[newideas99]

How is this going guys? :)

[adi776borate]

How is this going guys? :)

I'm on it. The normal inpainting (without reference image) is working good. There are some issues when reference image is passed.
I'll try fixing it and open a PR or a draft PR by tomorrow.

[newideas99]

@adi776borate this might help as well
https://arxiv.org/html/2502.03491v1
https://huggingface.co/charrywhite/LanPaint/tree/main