feat: Nunchaku Z-Image model to load and run LoRAs with native LoRALoader node provided by ComfyUI

[devgdovg]

Motivation

• Make Nunchaku Z-Image model loaded by NunchakuZImageDiTLoader be able to run with LoRAs
• Make LoRA loading/unloading process for Nunchaku Z-Image model be aligned with general LoRA Loader provided by ComfyUI, instead of implementing a customized LoRA loader for Nunchaku Z-Image only. See the screen shot below.

Modifications

• Create a new class ZImageModelPatcher that inherits comfy.model_patcher.ModelPatcher. The ZImageModelPatcher overrides a bunch of methods of its parent in order to inject LoRA loading/unloading for quantized SVDQ linear modules.
• Add a test case featured two cascaded native ComfyUI LoRA loaders.

Checklist

• Code is formatted using Pre-Commit hooks (run pre-commit run --all-files).
• Relevant unit tests are added in the tests/workflows directory following the guidance in the Contribution Guide.
• Reference images are uploaded to PR comments and URLs are added to test_cases.json.
• Additional test data (if needed) is registered in test_data/inputs.yaml.
• Additional models (if needed) are registered in scripts/download_models.py and test_data/models.yaml.
• Additional custom nodes (if needed) are added to .github/workflows/pr-test.yaml.
• For reviewers: If you're only helping merge the main branch and haven't contributed code to this PR, please remove yourself as a co-author when merging.
• Please feel free to join our Discord or WeChat to discuss your PR.

[devgdovg]

ref image is uploaded to huggingface in this session:
https://huggingface.co/datasets/nunchaku-tech/test-data/discussions/4