`createdAt` fields missing timezone #10

For example, on https://api.rocksky.app/xrpc/app.rocksky.actor.getActorScrobbles?limit=1&offset=0&did=t1c.dev the response

{
  "scrobbles": [
    {
      "id": "rec_d650q0od60d76dg67q60",
      // ...
      "createdAt": "2026-02-09T16:33:54"
    }
  ]
}

doesn't specify the timezone on createdAt. The correct response would be "createdAt": "2026-02-09T16:33:54Z" (the Z indicating UTC)