List plans

{
  "plans": [
    {
      "id": "plan_IhMUl3rrZ3",
      "name": "Premium Plan",
      "code": "premium_plan",
      "status": "active",
      "description": "Premium subscription plan.",
      "bill_timing": "advance",
      "billing_cycles": null,
      "free_units": 0,
      "invoice_name": "Premium Plan",
      "trial_period_days": 14,
      "meter_id": null,
      "meter_name": null,
      "meter_profile_id": null,
      "meter_profile_name": null,
      "created_at": "2025-02-14T17:33:40.843Z",
      "interval": {
        "frequency": 1,
        "unit": "month"
      },
      "price": {
        "model": "flat",
        "currency": "USD",
        "amount": 5000
      },
      "fees": []
    }
  ],
  "meta": {
    "request_id": "req_IhMUl3rrZ3",
    "current_page": 1,
    "per_page": 20,
    "total_count": 100
  }
}