refactor(graph,runner,test): 重构代码并清理冗余逻辑

1. 将Graph类改为frozen dataclass简化实现
2. 移除executors.py中的内置策略校验逻辑
3. 使用typing.get_args替代直接访问Strategy.__args__
4. 清理测试文件中冗余的无效参数测试用例
5. 统一替换测试中未使用的px.run调用返回值
6. 在pyproject.toml中添加pytest slow标记配置

pyproject.toml

@@ -78,6 +78,7 @@ show_missing = true
 
 [tool.pytest.ini_options]
 asyncio_default_fixture_loop_scope = "function"
+markers = ["slow: marks tests as slow (deselect with '-m \"not slow\"')"]
 
 [tool.basedpyright]
 exclude                           = ["**/.git", "**/.venv", "**/__pycache__", "**/build", "**/dist"]