add example for gpt-oss

[jssmith]

What was changed

Added an example using gpt-oss with a tool call.

Why?

Checklist

1. Closes

2. How was this tested:

3. Any docs updates needed?

[jssmith]

Client needs to be created outside of CustomModelProvider as otherwise we have sandboxing issues:

future: <Task finished name='Task-47 (workflow: GptOssWorkflow, id: litellm-gpt-oss-workflow-id, run: 019881a0-034a-7a48-a1e0-9412fa0b9bbb)' coro=<AsyncClient.aclose() done, defined at /Users/jssmith/t/samples-python-2/.venv/lib/python3.12/site-packages/httpx/_client.py:1978> exception=RestrictedWorkflowAccessError('Cannot access threading.local.__mro_entries__ from inside a workflow. If this is code from a module not used in a workflow or known to only be used deterministically from a workflow, mark the import as pass through.')>
Traceback (most recent call last):
  File "/Users/jssmith/t/samples-python-2/.venv/lib/python3.12/site-packages/httpx/_client.py", line 1985, in aclose
    await self._transport.aclose()
  File "/Users/jssmith/t/samples-python-2/.venv/lib/python3.12/site-packages/httpx/_transports/default.py", line 406, in aclose
    await self._pool.aclose()
  File "/Users/jssmith/t/samples-python-2/.venv/lib/python3.12/site-packages/httpcore/_async/connection_pool.py", line 353, in aclose
    await self._close_connections(closing_connections)
  File "/Users/jssmith/t/samples-python-2/.venv/lib/python3.12/site-packages/httpcore/_async/connection_pool.py", line 343, in _close_connections
    with AsyncShieldCancellation():
         ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/jssmith/t/samples-python-2/.venv/lib/python3.12/site-packages/httpcore/_synchronization.py", line 203, in __init__
    self._backend = current_async_library()
                    ^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/jssmith/t/samples-python-2/.venv/lib/python3.12/site-packages/httpcore/_synchronization.py", line 26, in current_async_library
    import sniffio
  File "/Users/jssmith/t/samples-python-2/.venv/lib/python3.12/site-packages/temporalio/worker/workflow_sandbox/_importer.py", line 497, in __call__
    return self.current(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/jssmith/t/samples-python-2/.venv/lib/python3.12/site-packages/temporalio/worker/workflow_sandbox/_importer.py", line 248, in _import
    mod = importlib.__import__(name, globals, locals, fromlist, level)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen importlib._bootstrap>", line 1466, in __import__
  File "<frozen importlib._bootstrap>", line 1387, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1331, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 935, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 999, in exec_module
  File "<frozen importlib._bootstrap>", line 488, in _call_with_frames_removed
  File "/Users/jssmith/t/samples-python-2/.venv/lib/python3.12/site-packages/sniffio/__init__.py", line 12, in <module>
    from ._impl import (
  File "/Users/jssmith/t/samples-python-2/.venv/lib/python3.12/site-packages/temporalio/worker/workflow_sandbox/_importer.py", line 497, in __call__
    return self.current(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/jssmith/t/samples-python-2/.venv/lib/python3.12/site-packages/temporalio/worker/workflow_sandbox/_importer.py", line 248, in _import
    mod = importlib.__import__(name, globals, locals, fromlist, level)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen importlib._bootstrap>", line 1470, in __import__
  File "<frozen importlib._bootstrap>", line 1387, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1331, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 935, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 999, in exec_module
  File "<frozen importlib._bootstrap>", line 488, in _call_with_frames_removed
  File "/Users/jssmith/t/samples-python-2/.venv/lib/python3.12/site-packages/sniffio/_impl.py", line 11, in <module>
    class _ThreadLocal(threading.local):
  File "/Users/jssmith/t/samples-python-2/.venv/lib/python3.12/site-packages/temporalio/worker/workflow_sandbox/_restrictions.py", line 1016, in __getattribute__
    state.assert_child_not_restricted(__name)
  File "/Users/jssmith/t/samples-python-2/.venv/lib/python3.12/site-packages/temporalio/worker/workflow_sandbox/_restrictions.py", line 852, in assert_child_not_restricted
    raise RestrictedWorkflowAccessError(
temporalio.worker.workflow_sandbox._restrictions.RestrictedWorkflowAccessError: Cannot access threading.local.__mro_entries__ from inside a workflow. If this is code from a module not used in a workflow or known to only be used deterministically from a workflow, mark the import as pass through.