feat: Refactor to use flake-parts and import inventory and users thru the flake parts

fleet/fleet-option.nix

@@ -59,6 +59,109 @@ let
       )
     );
   };
+  # Submodule defining the structure of a user account
+  userSubmodule = lib.types.submodule {
+    options = {
+      isNormalUser = lib.mkOption {
+        type = lib.types.bool;
+        default = true;
+      };
+      description = lib.mkOption {
+        type = lib.types.nullOr lib.types.str;
+        default = null;
+      };
+      extraGroups = lib.mkOption {
+        type = lib.types.listOf lib.types.str;
+        default = [ ];
+      };
+      hashedPassword = lib.mkOption {
+        type = lib.types.str;
+        default = "!";
+      };
+      extraPackages = lib.mkOption {
+        type = lib.types.listOf lib.types.package;
+        default = [ ];
+      };
+      excludePackages = lib.mkOption {
+        type = lib.types.listOf lib.types.package;
+        default = [ ];
+      };
+      homePackages = lib.mkOption {
+        type = lib.types.listOf lib.types.package;
+        default = [ ];
+      };
+      extraImports = lib.mkOption {
+        type = lib.types.listOf lib.types.path;
+        default = [ ];
+      };
+      external = lib.mkOption {
+        type = lib.types.nullOr (
+          lib.types.oneOf [
+            lib.types.path
+            lib.types.package
+            lib.types.attrs
+          ]
+        );
+        default = null;
+        description = ''
+          External user configuration module. Can be:
+          - A path to a local module directory
+          - A fetchGit/fetchTarball result pointing to a repository
+
+          The external module can contain:
+          - user.nix (optional): Sets athenix.users.<name> options AND home-manager config
+          - nixos.nix (optional): System-level NixOS configuration
+
+          Example: builtins.fetchGit { url = "https://github.com/user/dotfiles"; rev = "..."; }
+        '';
+      };
+      opensshKeys = lib.mkOption {
+        type = lib.types.listOf lib.types.str;
+        default = [ ];
+        description = "List of SSH public keys for the user.";
+      };
+      shell = lib.mkOption {
+        type = lib.types.nullOr (
+          lib.types.enum [
+            "bash"
+            "zsh"
+            "fish"
+            "tcsh"
+          ]
+        );
+        default = "bash";
+        description = "The shell for this user.";
+      };
+      editor = lib.mkOption {
+        type = lib.types.nullOr (
+          lib.types.enum [
+            "vim"
+            "neovim"
+            "emacs"
+            "nano"
+            "code"
+          ]
+        );
+        default = "neovim";
+        description = "The default editor for this user.";
+      };
+      useZshTheme = lib.mkOption {
+        type = lib.types.bool;
+        default = true;
+        description = "Whether to apply the system Zsh theme.";
+      };
+      useNvimPlugins = lib.mkOption {
+        type = lib.types.bool;
+        default = true;
+        description = "Whether to apply the system Neovim configuration.";
+      };
+      enable = lib.mkOption {
+        type = lib.types.bool;
+        default = false;
+        description = "Whether this user account is enabled on this system.";
+      };
+    };
+  };
 in
 {
   options.athenix = {
@@ -67,6 +170,11 @@ in
       description = "Hardware types definitions for the fleet.";
       type = lib.types.attrs;
     };
+    users = lib.mkOption {
+      type = lib.types.attrsOf userSubmodule;
+      default = { };
+      description = "User accounts configuration. Set enable=true for users that should exist on this system.";
+    };
   };
 
   config.athenix.hwTypes = lib.mkDefault (import ../hw { inherit inputs; });