curl --request GET \
  --url https://app.sendmux.ai/api/v1/mailboxes \
  --header 'Authorization: Bearer <token>'

{
  "ok": true,
  "data": [
    {
      "id": "mbx_clxxxxxxxxxxxxxxxxxxxxxxxxx",
      "email": "agent@acme.com",
      "display_name": "<string>",
      "quota_bytes": 123,
      "send_scope": {
        "type": "all",
        "provider_public_ids": [
          "<string>"
        ],
        "group_public_ids": [
          "<string>"
        ]
      },
      "status": "active",
      "created_at": "<string>"
    }
  ],
  "pagination": {
    "has_more": true,
    "next_cursor": "<string>"
  },
  "meta": {
    "request_id": "<string>"
  }
}