- Rename requirements.txt to _requirements.txt to avoid unintended self-install via PythonInstaller.
- Update flake.nix to provide Python with pip in both devShell and runtime closure.
- Generate a wrapper for pkgmgr that uses the pip-enabled interpreter.
- Adjust NixFlakeInstaller to correctly handle old profile removal and install outputs.
- Update run_command to support string commands and allow_failure.
- Improve integration test by adding nix profile cleanup and debugging output.
Reference: https://chatgpt.com/share/69345df2-a960-800f-8395-92a7c3a6629f
