CreateVideoExtensionRequest

{
    "partnerModelId": "ep-20260809114245-bzj48",
    "name": "Extend - Astronaut Story",
    "prompt": "Extend @video1 backward: The astronaut continues walking forward, spots a mysterious alien structure, and stops to scan it with his handheld radar.",
    "mode": 4,
    "resolution": 3,
    "ratio": 7,
    "duration": 1,
    "seconds": 6,
    "outputFormat": "mp4",
    "outputSound": true,
    "webHookUrl": "https://your-domain.com/webhook/video",
    "files": [
        {
            "assetId": "e3057cae-9907-4e92-ba2c-2936c0500a4d",
            "role": "reference_image"
        }
    ]
}