{
  "operation": "Mutate Timeline Project via Action-Based API (Create/Add Track/Add Asset/Attach Asset/Keyframe) with Keyframe-Level Adjustments",
  "method": "POST",
  "path": "/api/video/timeline",
  "request": {
    "action": "create",
    "projectId": "string",
    "durationMs": 1.0,
    "frameRate": 1.0,
    "type": "video",
    "name": "string",
    "sourceUrl": "string",
    "trackId": "string",
    "assetId": "string",
    "startMs": 1.0
  },
  "response": {
    "message": "Timeline updated"
  }
}