The `deprecated` field from OpenAPI operations is parsed but not exposed to templates

Describe the bug

The deprecated field on OpenAPI operation objects is parsed into the Operation schema model (operation.py#L31), but it is never carried over to the Endpoint dataclass that is passed to Jinja templates (openapi.py#L132-L152).

This means there is no way to check endpoint.deprecated in a custom template to conditionally emit deprecation warnings, docstring annotations, or @deprecated decorators.

The Endpoint dataclass is missing a deprecated: bool field, and the constructor at openapi.py#L419-L427 does not pass data.deprecated through.

Expected behavior

The Endpoint dataclass should include a deprecated: bool = False field, populated from data.deprecated during construction, so that templates can use {% if endpoint.deprecated %} to customize output for deprecated operations.

OpenAPI Spec File

Any spec with a deprecated operation, for example:

paths:
  /example:
    get:
      operationId: getExample
      deprecated: true
      responses:
        '200':
          description: OK

Desktop (please complete the following information):

• OS: macOS 26.3
• Python Version: 3.9.6
• openapi-python-client version: 0.28.2

Bắt đầu với model Operation trong openapi_python_client/schema/openapi_schema_pydantic/operation.py và dataclass Endpoint cùng constructor trong openapi_python_client/parser/openapi.py. Truy vết cách dữ liệu operation đến Endpoint được truyền cho các template Jinja, sau đó xác minh rằng một operation deprecated cung cấp endpoint.deprecated và mặc định là false khi không được chỉ định.