GET /api/v1/processors/:id/transactions

{
  "success": true,
  "transactions": [
    {
      "id": "txn_abc123",
      "type": "pos_payment",
      "amount": "150.00 SLE",
      "fee": "1.50 SLE",
      "status": "completed",
      "subscriber_id": "sub_xyz789",
      "created_at": "2025-01-15T10:30:00Z"
    }
  ],
  "total_count": 500,
  "message": "Transactions retrieved successfully"
}