fix(ci): add pytest-asyncio for async/streaming tests

The now-tier batch added test_async_stack and test_streaming but did not
declare pytest-asyncio in dev dependencies, causing 6 CI failures on a
clean pip install -e .[dev].

Co-authored-by: Daniel <DJLougen@users.noreply.github.com>

Author: cursoragent

pyproject.toml

@@ -63,10 +63,14 @@ monitor = ["pynvml>=2.0"]
 performance = ["hive-cpp>=0.1.0"]
 dev = [
     "pytest>=8.0",
+    "pytest-asyncio>=0.24",
     "pytest-cov>=4.1",
     "ruff>=0.5",
     "mypy>=1.8",
 ]
+
+[tool.pytest.ini_options]
+asyncio_mode = "auto"
 # Real-time observability: Prometheus, OpenTelemetry, JSONL export
 observability = [
     "prometheus-client>=0.20",