`default` property sibling to a `$ref` is ignored

Describe the bug
default property sibling to a $ref is ignored. OAS 3.1.X relies on JSON Schema 2020-12 which does not include the requirement that sibling properties to $ref should be ignored.

OpenAPI Spec File

{
  "openapi": "3.1.0",
  "info": {
    "title": "title",
    "summary": "summary",
    "description": "description",
    "version": "0.0.1"
  },
  "paths": {
    "/": {
      "get": {
        "parameters": [
          {
            "name": "default_lost1",
            "required": false,
            "schema": {
              "$ref": "#/components/schemas/String",
              "default": "lost"
            }
          },
          {
            "name": "default_lost2",
            "required": false,
            "schema": {
              "$ref": "#/components/schemas/DefaultString"
            }
          },
          {
            "name": "default_lost3",
            "schema": {
              "allOf": [
                {
                  "$ref": "#/components/schemas/DefaultString"
                }
              ]
            }
          }, 
          {
            "name": "default_kept",
            "schema": {
              "allOf": [
                {
                  "$ref": "#/components/schemas/String"
                }
              ],
              "default": "kept"
            }
          }
        ],
        "responses": {
          "200": {
            "description": "Successful Response",
            "content": {}
          }
        }
      }
    }
  },
  "components": {
    "schemas": {
      "String": {
        "type": "string"
      },
      "DefaultString": {
        "type": "string",
        "default": "component_default"
      }
    }
  }
}

Desktop (please complete the following information):

• OS: macOS 26.4.1
• Python Version: 3.11.13
• openapi-python-client version: 0.28.3

Additional context
The previous schema generates code like this:

def _get_kwargs(
    *,
    body: Object,
    default_lost1: str | Unset = UNSET,
    default_lost2: str | Unset = UNSET,
    default_lost3: str | Unset = UNSET,
    default_kept: str | Unset = 'kept',

) -> dict[str, Any]:

I would expect all defaults to be kept.

If anything else is needed I will be more than happy to provide it. Thank you for your time!

Commencez par reproduire le problème avec la spécification OpenAPI 3.1 du rapport et inspectez la sortie générée de _get_kwargs. Suivez la manière dont les valeurs par défaut des schémas sont gérées pour les frères directs de $ref, les schémas référencés et les wrappers allOf. Le travail est terminé lorsque les quatre valeurs par défaut, y compris component_default, sont conservées dans le client généré.