Oasis unet reconstruction

[ydu0117]

Summary

• Add OASIS inference plotting example
• Add OASIS U-Net checkpoint loading through the shared fastMRI U-Net module
• Enable OASIS k-space distortions and document reconstruction_only download link

Tests

• uv run pre-commit run --all-files
• uv run pytest

[MatthiasLen]

Dear @ydu0117 , thank you for the PR. I have reviewed it.

• there was some functionality missing related to automated model download. In my latest commit I have added SHA256 certified automated download. This means certification will fail if the model weights are updated. This it intentional to fix model weight versions etc. ... Good news is , the user gets the model automatically and no manual dowloading from GCP is needed. please have a look at my changes.
• I could resolve a small merge conflict
• I have added some missing dependencies in the pyproject.toml.

Open point I kindly ask you to support:
It could you add OASIS to the FastMRI reconstruction example in the same "lightweight way" as the other reconstructors ? Important: In case the OASIS and FastMRI dataset convention differ I would suggest to move this is a small separate adaptor class . The example code , the reconstructor API should not be "blown-up". If you have questions, please, ping me in teams or tag me here. Thanks 👍