nix-community/home-manager ? reverse-engineered prompt

Build me a way to manage my personal dotfiles, apps, and user settings with Nix, so I can keep my home environment reproducible and easy to roll back.

I want it to work for someone on NixOS, Darwin, or as a standalone setup, and I’d like a simple starting point that can grow over time. The goal is to let me define things like installed user packages, shell setup, editor config, terminal settings, and other home directory files in one place, then apply them cleanly from a single command.

Please make the setup feel practical and well documented, with examples for both flake based and channel based use if that makes sense. If you need to look up current docs online or check how Home Manager is usually configured, go ahead. I care most about something reliable, declarative, and easy enough for a beginner to start small with and expand later.