Upload model from remote URL (async)

Initiates an async download from a remote URL (Civitai, HuggingFace, etc.).

For Civitai/HuggingFace URLs, metadata is auto-extracted:

• Civitai: base_model, trained_words, source_arn, preview_url
• HuggingFace: repo_id, revision, source_arn

You can override auto-extracted metadata by providing explicit values.

When downloading from Civitai/HuggingFace, source is automatically populated with verified provenance. You cannot set source manually.