每一个字段，
都与实现完全一致。

# The response cookie scopes the task to this anonymous session.
curl -X POST https://vgent.com/api/v1/videos \
  -H 'Content-Type: application/json' \
  -H "Idempotency-Key: $(uuidgen)" \
  --cookie-jar vgent.cookies \
  -d '{"model":"vivid-1","mode":"text","prompt":"Neon koi swimming through a flooded Tokyo alley","resolution":"720P","aspect":"16:9","duration":5,"audio":true,"media":[],"advanced":{},"source":null}'

# Poll with the same cookie; any other session gets task_not_found.
curl https://vgent.com/api/v1/videos/b7f3c0a4-51d2-4c8e-9a17-2f6d0e5b3c91 --cookie vgent.cookies

const created = await fetch('/api/v1/videos', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
    'Idempotency-Key': crypto.randomUUID(),
  },
  body: JSON.stringify({
    model: 'vivid-1',
    mode: 'text',
    prompt: 'Neon koi swimming through a flooded Tokyo alley',
    resolution: '720P',
    aspect: '16:9',
    duration: 5,
    audio: true,
    media: [],
    advanced: {},
    source: null,
  }),
});

const { data, error } = await created.json();
if (error) throw new Error(`${error.code}: ${error.message}`);

// 202 Accepted returns { taskId, model }; the video does not exist yet.
let task;
do {
  await new Promise((resolve) => setTimeout(resolve, 3000));
  const polled = await fetch(`/api/v1/videos/${data.taskId}`, { cache: 'no-store' });
  task = (await polled.json()).data;
} while (task.status === 'pending' || task.status === 'processing');

// A failed generation still arrives as HTTP 200 with task.error set.
console.log(task.status === 'completed' ? task.videoUrl : task.error);

{
  "data": {
    "taskId": "b7f3c0a4-51d2-4c8e-9a17-2f6d0e5b3c91",
    "status": "completed",
    "model": "doubao-seedance-2.0",
    "videoUrl": "https://cdn.aivideoapi.ai/outputs/b7f3c0a4.mp4",
    "creditsConsumed": 190,
    "providerCredits": 190,
    "lastFrameUrl": "https://cdn.aivideoapi.ai/outputs/b7f3c0a4-last.jpg",
    "ratio": "16:9",
    "resolution": "720p",
    "duration": 5,
    "outputFormat": "mp4",
    "sourceToken": "eyJ0YXNrSWQiOiJiN2YzYzBhNCIsImV4cCI6MTc4OTE3MTgxMn0.dGFza190b2tlbl9zaWduYXR1cmU",
    "progress": 100,
    "estimatedSeconds": 0,
    "createdAt": 1789084800,
    "completedAt": 1789085412,
    "error": null
  },
  "error": null
}

{
  "data": {
    "taskId": "b7f3c0a4-51d2-4c8e-9a17-2f6d0e5b3c91",
    "model": "doubao-seedance-2.0"
  },
  "error": null
}

{
  "data": null,
  "error": {
    "code": "rate_limited",
    "message": "Too many requests.",
    "retryAfterSeconds": 47
  }
}