refactor: simplify module composition

modules/flake-parts.nix

@@ -4,6 +4,11 @@
   ...
 }:
 let
+  hostNames = [
+    "orion"
+    "polaris"
+    "zenith"
+  ];
   nixosModules = config.flake.modules.nixos;
 in
 {
@@ -11,22 +16,13 @@ in
 
   systems = [ "x86_64-linux" ];
 
-  flake.nixosConfigurations = {
-    orion = inputs.nixpkgs.lib.nixosSystem {
+  flake.nixosConfigurations = inputs.nixpkgs.lib.genAttrs hostNames (
+    name:
+    inputs.nixpkgs.lib.nixosSystem {
       specialArgs = { inherit inputs; };
-      modules = [ nixosModules.orion ];
-    };
-
-    polaris = inputs.nixpkgs.lib.nixosSystem {
-      specialArgs = { inherit inputs; };
-      modules = [ nixosModules.polaris ];
-    };
-
-    zenith = inputs.nixpkgs.lib.nixosSystem {
-      specialArgs = { inherit inputs; };
-      modules = [ nixosModules.zenith ];
-    };
-  };
+      modules = [ nixosModules.${name} ];
+    }
+  );
 
   perSystem =
     { pkgs, ... }: