Python generator actions can miss dependency imports, and Windows MSI trimming can select the wrong Python runtime. Supply generator PYTHONPATH and Windows DLL/stdlib environment, resolve WiX tools for Windows execution, and invoke msitrim.py with the selected Windows interpreter and wheel imports.

Depends on https://github.com/10gen/mongo/pull/63915, which is stacked on https://github.com/10gen/mongo/pull/63785.

The MSI analysis test checks packaging actions, dependency inputs, and the real mongoca custom-action DLL. This 11-file PR extracts the action-runtime portion of the former https://github.com/10gen/mongo/pull/63785.

Validation: runtime_pythonpath_test and template_renderer_python_path_analysis_test passed; buildscripts:msitrim built on macOS; formatting passed. MSI analysis/execution requires native Windows CI.