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

{
  "ok": true,
  "meta": {
    "request_id": "req_clxxxxxxxxxxxxxxxxxxxxxxxxx"
  },
  "data": {
    "window_days": 7,
    "providers": [
      {
        "provider_id": "<string>",
        "sent_today": 1,
        "total_7d": 1,
        "sent_7d": 1,
        "failed_7d": 1,
        "rejected_7d": 1,
        "pending_7d": 1
      }
    ]
  }
}