test/memory+runtime: cover store and client factory

Enable pytest-asyncio auto mode; assert default user, message
round-trip, and provider→client mapping including errors.

pyproject.toml

@@ -37,6 +37,11 @@ reportExplicitAny = "hint"
 reportImplicitStringConcatenation = "hint"
 reportImportCycles = "hint"
 
+[tool.pytest.ini_options]
+asyncio_mode = "auto"
+asyncio_default_fixture_loop_scope = "function"
+testpaths = ["tests"]
+
 [tool.pdm]
 distribution = true