curl --request GET \
  --url https://api.coldsend.pro/api/public/v1/analytics/campaigns \
  --header 'X-API-Key: <api-key>'

{
  "kpis": {
    "total_campaigns": 123,
    "total_sends": 123,
    "avg_open_rate": 123,
    "avg_reply_rate": 123,
    "avg_bounce_rate": 123
  },
  "campaigns": [
    {
      "campaign_id": "<string>",
      "name": "<string>",
      "status": "<string>",
      "total_leads": 123,
      "sent_count": 123,
      "open_count": 123,
      "reply_count": 123,
      "bounce_count": 123,
      "unsubscribe_count": 123,
      "open_rate": 123,
      "reply_rate": 123,
      "bounce_rate": 123,
      "launched_at": "<string>",
      "completed_at": "<string>"
    }
  ],
  "success": true,
  "message": "Analytics retrieved successfully"
}