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/README.md

@@ -0,0 +1,85 @@
+# NixOS Modules Directory Structure
+
+This directory contains reusable NixOS modules organized by functional domain for the Home-lab infrastructure.
+
+## Directory Organization
+
+### `common/`
+Core modules shared across all machines in the home lab:
+- `base.nix` - Modern CLI tools, aliases, and essential packages
+- `tty.nix` - Console configuration and theming
+- `nix.nix` - Nix/flakes configuration and optimization settings
+- `ssh.nix` - SSH server and security configurations
+- `networking.nix` - Basic networking and firewall settings
+
+### `desktop/`
+Desktop environment configurations for workstation machines:
+- `gnome.nix` - GNOME desktop environment setup
+- `cosmic.nix` - System76 COSMIC desktop configuration  
+- `sway.nix` - Sway window manager and Wayland setup
+- `fonts.nix` - Font packages and configurations
+- `audio.nix` - PipeWire/audio system setup
+
+### `development/`
+Development tools and environments:
+- `editors.nix` - Text editors (Emacs, Neovim, VSCode)
+- `languages.nix` - Programming languages and runtimes
+- `tools.nix` - Development utilities and CLI tools
+- `containers.nix` - Development container tools
+- `git.nix` - Git configuration and tools
+
+### `virtualization/`
+Virtualization and containerization:
+- `podman.nix` - Podman container runtime
+- `libvirt.nix` - KVM/QEMU virtualization
+- `incus.nix` - System container management
+- `docker.nix` - Docker runtime (if needed)
+
+### `services/`
+Network services primarily for SleeperService file server:
+- `nfs.nix` - Network File System server
+- `samba.nix` - SMB/CIFS file sharing
+- `backup.nix` - Automated backup services
+- `monitoring.nix` - System monitoring and alerting
+- `storage.nix` - ZFS and storage management
+- `media.nix` - Media server services (Jellyfin/Plex)
+
+### `users/`
+User management and shared user configurations:
+- `common.nix` - Shared user settings across machines
+- `groups.nix` - System groups and permissions
+- `security.nix` - User security policies
+
+## Usage
+
+Modules are imported in machine configurations like:
+
+```nix
+imports = [
+  ../../modules/common/base.nix
+  ../../modules/desktop/gnome.nix
+  ../../modules/virtualization/podman.nix
+];
+```
+
+## Design Philosophy
+
+- **Modular**: Each module has a single, clear responsibility
+- **Reusable**: Modules work across different machine types
+- **Composable**: Mix and match modules for different machine roles
+- **Documented**: Each module includes usage examples and options
+- **Testable**: Modules can be tested independently
+
+## Machine Profiles
+
+### CongenitalOptimist (Workstation)
+- All desktop modules
+- Development tools
+- Virtualization stack
+- User-focused configurations
+
+### sleeper-service (File Server)
+- Common base only
+- Service modules (NFS, Samba, backup)
+- No desktop environment
+- Server-focused configurations