curl --request GET \
  --url https://app.sendmux.ai/api/v1/mailbox/quotas \
  --header 'Authorization: Bearer <token>'

{
  "meta": {
    "request_id": "req_clxxxxxxxxxxxxxxxxxxxxxxxxx"
  },
  "data": [
    {
      "id": "<string>",
      "resource_type": "octets",
      "used": 123,
      "hard_limit": 123,
      "warn_limit": 123,
      "soft_limit": 123,
      "scope": "account",
      "name": "<string>",
      "types": [
        "<string>"
      ],
      "description": "<string>"
    }
  ],
  "pagination": {
    "has_more": true,
    "next_cursor": "<string>"
  }
}