- test_router_context_window_check_pre_call_check_out_group: replace deprecated
gpt-3.5-turbo-1106 (removed from model_cost, returns max_input_tokens=0) with
gpt-4.1-mini + mock_response
- test_async_fallbacks: filter "Task was destroyed but it is pending" messages
that leak from parallel test execution in CI
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>