curl -X GET "https://olive-gateway-a6ba.onrender.com/api/v1/subscribers/lookup?phone_number=0771234567" \
  -H "Authorization: Bearer olive_live_xxx"

{
  "found": true,
  "subscriber": {
    "id": "sub_abc123",
    "phone_number": "+23279123456",
    "first_name": "John",
    "last_name": "Doe",
    "kyc_level": 2,
    "status": "ACTIVE",
    "balance": "125,000.00 SLE"
  }
}