curl --request GET \
  --url https://app.autoposting.ai/api-proxy/billing/history \
  --header 'Authorization: Bearer <token>'

{
  "success": true,
  "data": {
    "invoices": [
      {
        "id": "inv_abc123",
        "amount": 4900,
        "currency": "usd",
        "status": "paid",
        "description": "Pro Plan - January 2024",
        "paidAt": "2024-01-01T00:00:00Z",
        "invoiceUrl": "https://..."
      }
    ]
  }
}