Add wan-2.1-t2v-1.3b

[labyrinth-ssr]

Resolves #<issue_number_goes_here>

Reference

Checklist

• [] I have read the Contribution Guidelines and used pre-commit hooks to format this commit.
• [] I have added all the necessary unit tests for my change. (run_model.py for model usage, test_outputs.py and/or model_validation_colab.ipynb for quality).
• [] (If using an LLM) I have carefully reviewed and removed all superfluous comments or unneeded, commented-out code. Only necessary and functional code remains.
• [] I have signed the Contributor License Agreement (CLA).

[google-cla]

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[jenriver]

Thanks for this contribution! I see that this is still in draft stage -- could you let us know when it's ready for review?

Also, please sign the Contribution License Agreements.