Honor retry-after headers when OpenAI requests a retry

[1fanwang]

When OpenAI answers an agent activity with x-should-retry: true and a retry-after header, the SDK drops that delay and uses the activity's configured interval. A server asking for 5 seconds can therefore get another request after 1 second. This change honors the server delay. Users can also opt out through RetryPolicy(non_retryable_error_types=["APIStatusError"]), including for concrete errors such as RateLimitError.

The status handler now converts every APIStatusError subclass to an ApplicationError whose type remains APIStatusError. The same raise carries the retry decision and parsed delay, so the explicit true and false headers still take precedence over the HTTP status.

How I tested it

Before: retry delay was lost

git checkout 35b24bb28edf40fc3e2d3c446ea77a0cba312f6f -- temporalio/contrib/openai_agents/_invoke_model_activity.py
uv run pytest tests/contrib/openai_agents/test_openai.py -k "retry_after or should_retry" -q --no-header

E           openai.APIStatusError: Something went wrong.
temporalio/contrib/openai_agents/_invoke_model_activity.py:315: APIStatusError
Results (1.19s):
         3 failed
         2 passed
        54 deselected

Before: the converted error had no type

git checkout c5724638be1d65c271ca3872138e3b176b4b2dd6 -- temporalio/contrib/openai_agents/_invoke_model_activity.py
uv run pytest tests/contrib/openai_agents/test_openai.py::test_retry_after_ms_propagated_when_server_requests_retry -q --no-header

E       assert None == "APIStatusError"

After

git checkout HEAD -- temporalio/contrib/openai_agents/_invoke_model_activity.py
uv run pytest tests/contrib/openai_agents/test_openai.py -k "exception_handling or retry_after" -q --no-header

....                                                                     [100%]
Results (16.15s):
         4 passed
        55 deselected
         3 warnings

The warnings are the existing workflow sandbox notices for pydantic_core imports.

[brianstrauch]

Thanks for the PR! Can we preserve APIStatusError instead of returning an untyped ApplicationError? I should be able to opt out of retry with RetryPolicy(non_retryable_error_types=["APIStatusError"]).

[brianstrauch]

Thank you!