dsh-python-tempfile-shim: Make Python temporary directory available in DSH Windows Sandbox

`dsh-python-tempfile-shim` is a temporary DeepSeek Harness (DSH) plugin maintained by AngelosZou under the MIT license, designed to address the issue of restricted Python temporary directories in Windows sandboxes. This plugin is not published to npm and requires local cloning for installation. Its core mechanism involves mounting the shell executor via a DSH plugin patch to automatically inject `PYTHONPATH` for restricted commands (such as `workspace-write` and `read-only`), and it includes a `sitecustomize.py` that makes `os.mkdir` ignore the mode parameter, allowing new directories to inherit the parent directory's ACL. The plugin overrides `pyt`