curl https://zeplo.ai/api/subscriptions/active/1 \
  -H "x-api-key: YOUR_API_KEY" \
  -H "x-api-secret: YOUR_API_SECRET" \
  -H "x-channel-id: YOUR_CHANNEL_ID"

{
  "success": true,
  "data": {
    "id": 1,
    "userId": 1,
    "planId": 2,
    "planName": "Professional",
    "status": "active",
    "startDate": "2026-01-01T00:00:00Z",
    "endDate": "2026-02-01T00:00:00Z",
    "autoRenew": true,
    "usage": {
      "contacts": { "used": 450, "limit": 5000 },
      "messages": { "used": 3200, "limit": 25000 },
      "channels": { "used": 2, "limit": 5 }
    },
    "createdAt": "2026-01-01T00:00:00Z"
  }
}