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

{
  "meta": {
    "request_id": "req_clxxxxxxxxxxxxxxxxxxxxxxxxx"
  },
  "data": {
    "old_state": "<string>",
    "new_state": "<string>",
    "has_more": true,
    "created": [
      "<string>"
    ],
    "updated": [
      "<string>"
    ],
    "destroyed": [
      "<string>"
    ],
    "updated_properties": [
      "<string>"
    ]
  }
}