Add NixOS module (#734)

* default.nix: fix "wavelength" typo

* Add nixos module

typo

fix

* nix: refactor and fix nix modules

* nix: fix NixOS module import

* nix: revert quickshell option change

* nix: fix nixosModules dmsPkgs definition

---------

Co-authored-by: LuckShiba <luckshiba@protonmail.com>

distro/nix/nixos.nix

@@ -0,0 +1,36 @@
+{
+    config,
+    pkgs,
+    lib,
+    dmsPkgs,
+    ...
+}: let
+    cfg = config.programs.dankMaterialShell;
+    common = import ./common.nix {inherit config pkgs lib dmsPkgs;};
+in {
+    imports = [
+        ./options.nix
+    ];
+
+    config = lib.mkIf cfg.enable
+    {
+        environment.etc."xdg/quickshell/dms".source = "${dmsPkgs.dankMaterialShell}/etc/xdg/quickshell/dms";
+
+        systemd.user.services.dms = lib.mkIf cfg.systemd.enable {
+            description = "DankMaterialShell";
+            path = [cfg.quickshell.package];
+
+            partOf = ["graphical-session.target"];
+            after = ["graphical-session.target"];
+            wantedBy = ["graphical-session.target"];
+            restartTriggers = lib.optional cfg.systemd.restartIfChanged common.qmlPath;
+
+            serviceConfig = {
+                ExecStart = lib.getExe dmsPkgs.dmsCli + " run --session";
+                Restart = "on-failure";
+            };
+        };
+
+        environment.systemPackages = [cfg.quickshell.package] ++ common.packages;
+    };
+}