fix(sdk): add pytest-asyncio dev dependency for async test support

The new test_emit_tool_call_optional_id.py uses async test methods
decorated with @pytest.mark.asyncio, but pytest-asyncio was missing
from dev dependencies — causing all 11 async tests to fail in CI
across all Python versions (3.10–3.14).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: mxmzb

sdk-python/pyproject.toml

@@ -48,4 +48,4 @@ requires = ["poetry-core"]
 build-backend = "poetry.core.masonry.api"
 
 [dependency-groups]
-dev = ["pytest (>=9.0.2,<10.0.0)"]
+dev = ["pytest (>=9.0.2,<10.0.0)", "pytest-asyncio (>=1.0.0,<2.0.0)"]