z-image support npu

[luren55]

What does this PR do?

Notice: Here is a PR extraction from #12979 to support z-image runs on NPU.

Issue: The Diffusers Z-Image pipeline fails on Ascend NPU because aclnnIndex lacks support for complex64. When freqs_cis is stored as a complex tensor on the NPU and then indexed, the call crashes.

Fix: Rework the RoPE frequency handling so that the NPU never needs to index complex64 tensors.

Running Environment:
I run this model base on cache-dit(https://github.com/vipshop/cache-dit/) which depends on diffusers to inference.

Command:
python3 generate.py zimage --model-path /home/weights/Z-Image-Turbo --attn _native_npu

Error before fixed:

Result after fixed:

Before submitting

• This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
• Did you read the contributor guideline?
• Did you read our philosophy doc (important for complex PRs)?
• Was this discussed/approved via a GitHub issue or the forum? Please add a link to it if that's the case.
• Did you make sure to update the documentation with your changes? Here are the
  documentation guidelines, and
  here are tips on formatting docstrings.
• Did you write any new necessary tests?

Who can review?

Anyone in the community is free to review the PR once the tests have passed. Feel free to tag
members/contributors who may be interested in your PR.

[luren55]

@yiyixuxu Hello, here is an extracion from the previous PR(#12979), can you review this PR? Thank you.

[yiyixuxu]

thanks!

[yiyixuxu]

@bot style

[HuggingFaceDocBuilderDev]

The docs for this PR live here. All of your documentation changes will be reflected on that endpoint. The docs are available until 30 days after the last update.

[yiyixuxu]

@bot /style

[github-actions]

Style fix runs successfully without any file modified.

[yiyixuxu]

can you run make fix-copies?