curl --request POST \
  --url https://api.opennote.com/v1/interactives/practice/grade \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{
  "problem": {
    "problem_type": "mcq",
    "problem_statement": "<string>",
    "correct_answer": "<string>",
    "difficulty": "medium",
    "answer_choices": {},
    "explanation": "<string>",
    "scoring_details": "<string>",
    "include_graph": false,
    "graph_description": "<string>",
    "graph_url": "<string>",
    "user_answer": "<string>"
  }
}'

{
  "success": true,
  "timestamp": "<string>",
  "score": 123,
  "explanation": "<string>",
  "max_score": 123,
  "percentage": 123
}