curl -X GET https://api.rapidcall.ai/api/billing/invoices \
  -H "Authorization: Bearer YOUR_API_KEY"

{
  "invoices": [
    {
      "id": "inv_2a3b4c5d",
      "number": "RC-2026-0042",
      "status": "paid",
      "totalAmount": 287.54,
      "currency": "USD",
      "issuedAt": "2026-04-01T00:00:00Z",
      "paidAt": "2026-04-01T06:12:00Z",
      "periodStart": "2026-03-01T00:00:00Z",
      "periodEnd": "2026-03-31T23:59:59Z",
      "stripeInvoiceUrl": "https://invoice.stripe.com/i/acct_1abc/inv_xyz"
    },
    {
      "id": "inv_6e7f8g9h",
      "number": "RC-2026-0031",
      "status": "paid",
      "totalAmount": 198.22,
      "currency": "USD",
      "issuedAt": "2026-03-01T00:00:00Z",
      "paidAt": "2026-03-01T08:45:00Z",
      "periodStart": "2026-02-01T00:00:00Z",
      "periodEnd": "2026-02-28T23:59:59Z",
      "stripeInvoiceUrl": "https://invoice.stripe.com/i/acct_1abc/inv_abc"
    },
    {
      "id": "inv_0i1j2k3l",
      "number": "RC-2026-0015",
      "status": "draft",
      "totalAmount": 142.87,
      "currency": "USD",
      "issuedAt": null,
      "paidAt": null,
      "periodStart": "2026-04-01T00:00:00Z",
      "periodEnd": "2026-04-30T23:59:59Z",
      "stripeInvoiceUrl": null
    }
  ]
}