curl -X GET "https://olive-gateway-a6ba.onrender.com/api/v1/cards" \
  -H "Authorization: Bearer olive_live_xxx"

{
  "cards": [
    {
      "serial": "OLIV0001",
      "mac_address": "AA:BB:CC:DD:EE:01",
      "type": "PARENT",
      "status": "ACTIVE",
      "subscriber_id": "sub_abc123",
      "subscriber_name": "John Doe",
      "linked_at": "2025-01-15T10:30:00Z"
    },
    {
      "serial": "OLIV0002",
      "mac_address": "AA:BB:CC:DD:EE:02",
      "type": "CHILD",
      "status": "ACTIVE",
      "subscriber_id": "sub_abc123",
      "parent_serial": "OLIV0001",
      "daily_limit": 5000000,
      "linked_at": "2025-01-16T14:00:00Z"
    },
    {
      "serial": "OLIV0003",
      "mac_address": "AA:BB:CC:DD:EE:03",
      "type": null,
      "status": "UNASSIGNED",
      "subscriber_id": null,
      "created_at": "2025-01-01T00:00:00Z"
    }
  ],
  "total_count": 1500,
  "limit": 50,
  "offset": 0
}