docs: update documentation for refactored structure

- Update NAMESPACE.md: filesystem.device and swapSize defaults now null
- Update README.md: add 'Using Athenix as a Library' section with lib.mkFleet
- Update copilot-instructions.md: reflect new directory structure and defaults
- Update EXTERNAL_MODULES.md: correct paths from variants/ and glue/ to hw/ and fleet/
- Update PROXMOX_LXC.md: update hardware type path reference

.github/copilot-instructions.md

@@ -26,8 +26,8 @@ This is a **NixOS system configuration repository** that uses:
 - **`flake.nix`**: Entry point - inputs and outputs only
 - **`inventory.nix`**: Fleet definitions - host configurations
 - **`users.nix`**: User account definitions
-- **`variants/`**: Hardware type modules (desktop, laptop, surface, lxc, wsl, etc.)
-- **`glue/`**: Fleet generation logic and common system configuration
+- **`hw/`**: Hardware type modules (desktop, laptop, surface, lxc, wsl, etc.)
+- **`fleet/`**: Fleet generation logic and common system configuration
 - **`sw/`**: Software configurations by system type
 - **`installer/`**: Build artifact generation (ISO, LXC, etc.)
 - **`templates/`**: Templates for external configurations
@@ -45,9 +45,12 @@ All Innovation Factory-specific options MUST use the `athenix` namespace:
 ### Host Options (`athenix.host.*`)
 ```nix
 athenix.host = {
-  filesystem.device = "/dev/sda";      # Boot disk
-  filesystem.swapSize = "32G";         # Swap size
-  buildMethods = [ "iso" ];            # Artifact types
+  filesystem.device = "/dev/nvme0n1"; # Boot disk (default: null)
+  filesystem.swapSize = "32G";         # Swap size (default: null)
+  buildMethods = [ "installer-iso" ];  # Artifact types (defined in sw/gc.nix)
+  useHostPrefix = true;                # Hostname prefix behavior
+  wsl.user = "username";               # WSL default user
+};
   useHostPrefix = true;                # Hostname prefix behavior
   wsl.user = "username";               # WSL default user
 };
@@ -114,6 +117,17 @@ athenix.forUser = "username";            # Convenience: enable user + set WSL us
 3. System modules: Provide `default.nix` that accepts `{ inputs, ... }`
 4. Reference in `inventory.nix` or `users.nix` using `builtins.fetchGit`
 
+#### Using Athenix as a Library
+External flakes can use Athenix's fleet generator:
+```nix
+outputs = { athenix, ... }: {
+  nixosConfigurations = athenix.lib.mkFleet {
+    fleet = import ./custom-inventory.nix;
+    hwTypes = import ./custom-hardware.nix;
+  };
+};
+```
+
 ## Important Constraints
 
 ### What NOT to Do

README.md

@@ -54,7 +54,7 @@ users.nix                 # User account definitions
 
 flake.lock                # Locked dependency versions
 
-variants/                 # Hardware type modules (exportable as nixosModules)
+hw/                 # Hardware type modules (exportable as nixosModules)
 ├── default.nix           # Auto-exports all variant types
 ├── nix-desktop.nix       # Desktop workstations
 ├── nix-laptop.nix        # Laptop systems
@@ -64,8 +64,8 @@ variants/                 # Hardware type modules (exportable as nixosModules)
 ├── nix-zima.nix          # ZimaBoard systems
 └── nix-ephemeral.nix     # Diskless/netboot systems
 
-glue/                     # Fleet generation and common configuration
-├── fleet.nix             # Processes inventory.nix to generate all hosts
+fleet/                    # Fleet generation and common configuration
+├── default.nix           # Processes inventory.nix to generate all hosts
 ├── common.nix            # Common NixOS configuration (all hosts)
 ├── boot.nix              # Boot and filesystem configuration
 └── user-config.nix       # User account and home-manager integration
@@ -233,6 +233,35 @@ nix flake show
 
 **See [docs/BUILDING.md](docs/BUILDING.md) for complete guide.**
 
+### Using Athenix as a Library
+
+Import Athenix in your own flake to use its fleet generation logic with custom inventory:
+
+```nix
+{
+  inputs.athenix.url = "git+https://git.factory.uga.edu/UGA-Innovation-Factory/athenix.git";
+  
+  outputs = { self, athenix, ... }: {
+    # Generate configurations with custom fleet and hardware types
+    nixosConfigurations = athenix.lib.mkFleet {
+      fleet = import ./my-inventory.nix;
+      hwTypes = import ./my-hardware-types.nix;
+    };
+    
+    # Or use individual modules
+    nixosConfigurations.myhost = nixpkgs.lib.nixosSystem {
+      modules = [
+        athenix.nixosModules.hw.nix-desktop  # Use Athenix hardware configs
+        athenix.nixosModules.sw              # Use Athenix software configs
+        ./configuration.nix
+      ];
+    };
+  };
+}
+```
+
+**Exported modules:** `nix-desktop`, `nix-laptop`, `nix-surface`, `nix-lxc`, `nix-wsl`, `nix-ephemeral`, `nix-zima`, `sw`, `common`
+
 ## System Types
 
 Set via `athenix.sw.type`:

docs/EXTERNAL_MODULES.md

@@ -115,8 +115,8 @@ server-config/
 
 When a host is built, modules load in this order:
 
-1. Hardware type module (from `variants/nix-*.nix`)
-2. Common system configuration (from `glue/common.nix`)
+1. Hardware type module (from `hw/nix-*.nix`)
+2. Common system configuration (from `fleet/common.nix`)
 3. Software type module (from `sw/{type}/`)
 4. User NixOS modules (from `users.nix` - `nixos.nix` files)
 5. Device-specific overrides (from `inventory.nix`)

docs/NAMESPACE.md

@@ -17,9 +17,9 @@ Hardware and boot-related settings.
 
 Boot disk device path.
 
-**Type:** String
+**Type:** String or null
 
-**Default:** `"/dev/sda"`
+**Default:** `null` (must be set by hardware type or per-host)
 
 **Example:**
 ```nix
@@ -30,9 +30,9 @@ athenix.host.filesystem.device = "/dev/nvme0n1";
 
 Swap partition size.
 
-**Type:** String (size with unit, e.g., `"32G"`, `"2G"`)
+**Type:** String (size with unit, e.g., `"32G"`, `"2G"`) or null
 
-**Default:** `"32G"`
+**Default:** `null` (must be set by hardware type or per-host)
 
 **Example:**
 ```nix

installer/PROXMOX_LXC.md

@@ -46,7 +46,7 @@ Add the host to `inventory.nix` with the `nix-lxc` type or ensure it has the app
 }
 ```
 
-Your host type configuration (`variants/nix-lxc.nix`) should include:
+Your host type configuration (`hw/nix-lxc.nix`) should include:
 
 ```nix
 {