curl --request GET \
  --url https://m2m-backend-qa.up.railway.app/partner/links/{linkId}/activity \
  --header 'X-API-Key: <api-key>'

{
  "success": true,
  "data": {
    "linkId": "link_acme_a1b2c3d4e5f6",
    "activities": [
      {
        "activityId": "act_a1b2c3",
        "type": "link.opened",
        "actor": "user",
        "timestamp": "2026-02-10T13:00:00.000Z",
        "status": "success",
        "data": {},
        "error": "<string>",
        "durationMs": 1250
      }
    ]
  }
}