curl --request GET \
  --url https://api.example.com/cabinet/admin/campaigns/{campaign_id}/chart-data \
  --header 'Authorization: Bearer <token>'

{
  "campaign_id": 123,
  "period_comparison": {
    "current": {
      "days": 123,
      "referrals_count": 0,
      "earnings_kopeks": 0
    },
    "previous": {
      "days": 123,
      "referrals_count": 0,
      "earnings_kopeks": 0
    },
    "referrals_change": {
      "absolute": 0,
      "percent": 0,
      "trend": "stable"
    },
    "earnings_change": {
      "absolute": 0,
      "percent": 0,
      "trend": "stable"
    }
  },
  "total_deposits_kopeks": 0,
  "total_spending_kopeks": 0,
  "daily_stats": [],
  "top_registrations": []
}