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/virtualization/libvirt.nix

@@ -0,0 +1,21 @@
+{ config, pkgs, ... }: {
+  virtualisation.libvirtd = {
+    enable = true;
+    qemu = {
+      package = pkgs.qemu_kvm;
+      runAsRoot = true;
+      swtpm.enable = true;
+      ovmf = {
+        enable = true;
+        packages = [ pkgs.OVMFFull.fd ];
+      };
+    };
+  };
+  
+  environment.systemPackages = with pkgs; [
+    qemu_kvm
+    libvirt
+    virt-manager
+    virt-viewer
+  ];
+}