The `pytest-asyncio` package is required for the async tests in
tests/test_sdk.py but is listed only under optional-dependencies.
Without it, `pytest tests/` silently fails 4 tests without any
error message — the tests just aren't collected.
Add a note to the Build and test section so developers know to
run `pip install -e ".[test]"` when running tests.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
sdk-dev