curl --request GET \
  --url https://api.engagefabric.com/api/v1/analytics/retention

{
  "cohorts": [
    {
      "cohortId": "<string>",
      "cohortLabel": "Week 1 (Jan 6-12)",
      "playerCount": 123,
      "retention": {
        "day1": 123,
        "day7": 123,
        "day14": 123,
        "day30": 123,
        "day60": 123,
        "day90": 123
      },
      "engagement": {
        "avgXp": 123,
        "avgLevel": 123,
        "avgQuestsCompleted": 123
      }
    }
  ],
  "averages": {
    "day1": 123,
    "day7": 123,
    "day14": 123,
    "day30": 123
  }
}