curl --request POST \
  --url https://app.sendmux.ai/api/v1/mailbox/folders \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "name": "<string>"
}
'

{
  "meta": {
    "request_id": "req_clxxxxxxxxxxxxxxxxxxxxxxxxx"
  },
  "data": {
    "id": "<string>",
    "name": "<string>",
    "parent_id": "<string>",
    "role": "<string>",
    "sort_order": 123,
    "total_messages": 123,
    "unread_messages": 123,
    "can_add_items": true
  }
}