curl -X POST "https://demo.api.vultlocal.com/api/v1/wallet/fund-from-vult" \
  -H "Authorization: Bearer olive_live_xxx" \
  -H "Content-Type: application/json" \
  -d '{
    "subscriber_id": "sub_abc123",
    "vult_wallet_id": "vult_xyz789",
    "amount": "500.00",
    "transaction_ref": "VULT-TXN-123456",
    "pin": "1234"
  }'

{
  "success": true,
  "message": "Wallet funded successfully",
  "transaction_id": "txn_fund_abc123",
  "amount": "500.00 SLE",
  "new_balance": "1,500.00 SLE",
  "vult_ref": "VULT-TXN-123456"
}

{
  "success": false,
  "error": "VULT wallet has insufficient balance",
  "code": "VULT_INSUFFICIENT_FUNDS"
}