feat: initial NixOS home lab infrastructure setup

- Add modular flake-based NixOS configuration
- Implement GitOps foundation with CI/CD pipeline
- Create comprehensive documentation and branching strategy
- Add modular desktop environments (GNOME, Cosmic, Sway)
- Configure virtualization stack (Incus, Libvirt, Podman)
- Set up development tools and hardware-specific modules
- Establish user configuration with literate programming support

This commit represents the completion of Phase 1: Flakes Migration
with modular configuration, virtualization, and GitOps foundation.

modules/users/geir.nix

@@ -0,0 +1,44 @@
+{ config, pkgs, ... }: {
+  # User configuration for geir
+  users.users.geir = {
+    isNormalUser = true;
+    extraGroups = [ "networkmanager" "wheel" "libvirt" "incus-admin" "podman" ];
+    shell = pkgs.zsh;
+    packages = with pkgs; [
+      # Browsers
+      chromium
+      vivaldi
+      vivaldi-ffmpeg-codecs
+      nyxt
+      firefox
+
+      # Terminal and shell tools
+      starship
+      fastfetch
+      hyfetch
+      nerdfetch
+      zellij
+      neo-cowsay
+      fortune
+      clolcat
+
+      # Audio and system control
+      ncpamixer
+      pavucontrol
+
+      # Desktop applications
+      gimp
+      obs-studio
+      vesktop
+      koodo-reader
+      
+      # System management
+      virt-manager
+      gnome-tweaks
+      beauty-line-icon-theme
+
+      # Emacs integration
+      emacsPackages.vterm
+    ];
+  };
+}