refactor: Fleet and sw behind mkIf guards

sw/ghostty.nix

@@ -1,4 +1,6 @@
 {
+  config,
+  lib,
   pkgs,
   ...
 }:
@@ -10,7 +12,11 @@
 # It reconstructs the terminfo database from the provided definition and
 # adds it to the system packages.
 
+with lib;
+
 let
+  cfg = config.athenix.sw;
+
   ghostty-terminfo = pkgs.runCommand "ghostty-terminfo" { } ''
     mkdir -p $out/share/terminfo
     cat > ghostty.info <<'EOF'
@@ -99,5 +105,7 @@ let
   '';
 in
 {
-  environment.systemPackages = [ ghostty-terminfo ];
+  config = mkIf cfg.enable {
+    environment.systemPackages = [ ghostty-terminfo ];
+  };
 }

sw/python.nix

@@ -18,10 +18,27 @@ let
   cfg = config.athenix.sw.python;
 in
 {
-  options.athenix.sw.python = {
-    enable = mkEnableOption "Python development tools (pixi, uv)" // {
-      default = true;
+  options.athenix.sw.python = lib.mkOption {
+    type = lib.types.submodule {
+      options = {
+        enable = lib.mkOption {
+          type = lib.types.bool;
+          default = true;
+          description = ''
+            Enable Python development tools (pixi, uv).
+
+            Provides:
+            - pixi: Fast, cross-platform package manager for Python
+            - uv: Extremely fast Python package installer and resolver
+
+            These tools manage project-based dependencies rather than global
+            Python packages, avoiding conflicts and improving reproducibility.
+          '';
+        };
+      };
     };
+    default = { };
+    description = "Python development environment configuration.";
   };
 
   config = mkIf cfg.enable {

sw/update-ref.nix

@@ -1,6 +1,18 @@
-{ pkgs, ... }:
 {
-  environment.systemPackages = with pkgs; [
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+
+with lib;
+
+let
+  cfg = config.athenix.sw;
+in
+{
+  config = mkIf cfg.enable {
+    environment.systemPackages = with pkgs; [
     python3
     git
     (pkgs.writeShellScriptBin "update-ref" ''
@@ -508,4 +520,5 @@
       printf "  rev = %s\n" "$CUR_REV" >&2
     '')
   ];
+  };
 }