[Feat] entrypoint like diffusers

[Musisoul]

单卡

python examples/simple_launch.py

# examples/simple_launch.py
from lightx2v import LightGenerator

generator = LightGenerator(
    model_path="/path/to/Wan2.1-T2V-1.3B",
    model_cls="wan2.1",
    task="t2v",
)

video_path = generator.generate(
    prompt="Two anthropomorphic cats in comfy boxing gear and bright gloves fight intensely on a spotlighted stage.",
    negative_prompt="镜头晃动，色调艳丽，过曝，静态，细节模糊不清，字幕，风格，作品，画作，画面，静止，整体发灰，最差质量，低质量，JPEG压缩残留，丑陋的，残缺的，多余的手指，画得不好的手部，画得不好的脸部，畸形的，毁容的，形态畸形的肢体，手指融合，静止不动的画面，杂乱的背景，三条腿，背景人很多，倒着走",
    seed=42,
    save_result_path="output.mp4",
)

多卡

export CUDA_VISIBLE_DEVICES=0,1,2,3,4,5,6,7
torchrun --nproc_per_node=8 examples/multi_launch.py