feat: simplify flake.nix

lib/nixosSystem.nix

@@ -0,0 +1,35 @@
+{
+  nixpkgs,
+  home-manager,
+  nixos-generators,
+  system,
+  specialArgs,
+  nixos-modules,
+  home-module,
+}: let
+  username = specialArgs.username;
+in
+  nixpkgs.lib.nixosSystem {
+    inherit system specialArgs;
+    modules =
+      nixos-modules
+      ++ [
+        nixos-generators.nixosModules.all-formats
+        {
+          # formatConfigs.iso = {config, ...}: {};
+          formatConfigs.proxmox = {config, ...}: {
+            # custom proxmox's image name
+            proxmox.qemuConf.name = "${config.networking.hostName}-nixos-${config.system.nixos.label}";
+          };
+        }
+
+        home-manager.nixosModules.home-manager
+        {
+          home-manager.useGlobalPkgs = true;
+          home-manager.useUserPackages = true;
+
+          home-manager.extraSpecialArgs = specialArgs;
+          home-manager.users."${username}" = home-module;
+        }
+      ];
+  }