Nix-grove: Configuration framework for flake-parts

AI USAGE: I used ChatGPT (GPT-5.6-Sol) to assist with design and planning, and Pi with GPT-5.6-Luna via openai-codex to help with implementation Sort of an “alternative” to the Dendritic pattern. Still is about importing a bunch of flake-parts modules, but uses the module system for more, instead of import=enable.