fix(openapi): update shipping cost calculation in OAS to include transport type and estimated delivery date

[alejorrojas]

Proposed changes on /shipping/cost API

Summary of Changes

• Request: Added required transport_type field
• Response: Added estimated_delivery_at and delivery_address fields

Request Body

Before:

{
  "delivery_address": {
    "street": "Av. Dirac 1234",
    "city": "Resistencia", 
    "state": "Chaco",
    "postal_code": "H3500ABC",
    "country": "AR"
  },
  "products": [
    {
      "id": 1,
      "quantity": 2
    }
  ]
}

After:

{
  "delivery_address": {
    "street": "Av. Dirac 1234",
    "city": "Resistencia",
    "state": "Chaco", 
    "postal_code": "H3500ABC",
    "country": "AR"
  },
  "transport_type": "air",
  "products": [
    {
      "id": 1,
      "quantity": 2
    }
  ]
}

Response Body

Before:

{
  "currency": "ARS",
  "total_cost": 45.5,
  "transport_type": "air",
  "products": [
    {
      "id": 1,
      "cost": 20.0,
      "quantity": 2
    }
  ]
}

After:

{
  "currency": "ARS",
  "total_cost": 45.5,
  "transport_type": "air",
  "estimated_delivery_at": "2025-10-01T00:00:00Z",
  "delivery_address": {
    "street": "Av. Dirac 1234",
    "city": "Resistencia",
    "state": "Chaco",
    "postal_code": "H3500ABC",
    "country": "AR"
  },
  "products": [
    {
      "id": 1,
      "cost": 20.0,
      "quantity": 2
    }
  ]
}