[chore] Add diffusers-format example to LongCatAudioDiTPipeline

[RuixiangMa]

What does this PR do?

• add diffusers-format example(repo_id: ruixiangma/LongCat-AudioDiT-1B-Diffusers)
• support seed parameter

import soundfile as sf
import torch
from diffusers import LongCatAudioDiTPipeline

pipeline = LongCatAudioDiTPipeline.from_pretrained(
    "ruixiangma/LongCat-AudioDiT-1B-Diffusers",
    torch_dtype=torch.bfloat16,
)
pipeline = pipeline.to("cuda")

prompt = "A calm ocean wave ambience with soft wind in the background."
audio = pipeline(
    prompt,
    audio_duration_s=5.0,
    num_inference_steps=20,
    guidance_scale=4.0,
    generator=torch.Generator("cuda").manual_seed(42),
).audios[0, 0]

sf.write("output.wav", audio, pipeline.sample_rate)

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[RuixiangMa]

@dg845 I uploaded a Diffusers-format repository, updated usage docs.

[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.

[dg845]

nit: I think it might be more clear here if we clarify how the pipeline handles mono and stereo outputs.

[RuixiangMa]

Added mono/stereo clarification in Tips

[dg845]

@bot /style

[github-actions]

Style bot fixed some files and pushed the changes.

[dg845]

Thanks for the follow-up PR! Left a few small comments/suggestions :).

[RuixiangMa]

Thanks for the follow-up PR! Left a few small comments/suggestions :).

Fixed, PTAL

[dg845]

@bot /style

[github-actions]

Style bot fixed some files and pushed the changes.

[dg845]

Thanks! (BTW, you can fix the code style with make style and make quality.)

[dg845]

Merging as the CI failures are unrelated.