I am new to jolt transformation. what would be the jolt spec to transform my source json

{
    "version": "123",
    "payload" : {
        "details": {
            "payload_json": "{"FName":"rishi","LName":"dx","Id":"ABC123","aadharId":"XYZ22"}"
        }
    }
}

to target json

{
    "firstName": "rishi",
    "lastName": "dx",
    "id": "ABC123",
    "officialIds": [
        {
            "type":"aadhar",
            "value": "XYZ22"
        }
    ]
}

I tried using Google Gemini and Micosoft Copilot to get the jolt spec, but neither of them are generating correct spec.