## Layout
```
.
├── config             # Config files not written in Nix
├── default.nix        # Defines module, system-level config,
├── disk-config.nix    # Disks, partitions, and filesystems
├── files.nix          # Non-Nix, static configuration files (now immutable!)
├── home-manager.nix   # Defines user programs
├── packages.nix       # List of packages to install for NixOS
├── secrets.nix        # Age-encrypted secrets with agenix
```