Add ROCm Dockerfile

[robertosw]

Summary

Added the Dockerfile for building a ROCm image. I am using this image locally for the cli - it works as expected.

I can run it with

$ podman run --rm \
     --device /dev/dri \
     --device /dev/kfd \
     --group-add video \
     -v ./models:/models:ro \
     -v ../output:/output \
     -v ./ref-images:/ref-images:ro \
     localhost/sd-rocm --color <and more cli args>

This was AI generated - if thats relevant for this repo.

• I have read and confirmed this PR follows the contribution guidelines.

[leejet]

Please address the following before merging:

• Disable GGML_NATIVE or use the dynamic CPU variants setup from the Vulkan/CUDA Dockerfiles. The default -march=native ties the image to the build host’s CPU features and can cause Illegal instruction on another machine.
• Add a ROCm run example to docs/docker.md, including --device=/dev/kfd --device=/dev/dri and any required group permissions. The existing generic run command does not expose the AMD GPU to the container.