Add DMS configuration enhancements and new default settings

- Introduced a new private default settings file for Dank Material Shell (DMS) to manage user-specific settings.
- Updated DMS home-manager module to generate a settings seed file, merging extra right-bar widgets into the first-run configuration.
- Added support for dynamic inclusion of DMS window rules based on user configuration.
- Enhanced the Niri configuration with a preference for no client-side decorations and improved keybindings for bar toggling.

modules/desktop/niri/default.nix

@@ -14,6 +14,7 @@ let
       };
       input."warp-mouse-to-focus" = _: { };
       layout.gaps = 5;
+      prefer-no-csd = true;
 
       window-rules = [
         {
@@ -62,7 +63,7 @@ let
 "Mod+N"."spawn-sh" = "dms ipc call notepad toggle"; #TODO[epic=Binds] This should only be set if having dms
 "Mod+Shift+N"."spawn-sh" = "dms ipc call notifications toggle"; #TODO[epic=Binds] This should only be set if having dms
 "Mod+M"."spawn-sh" = "dms ipc call processlist toggle"; #TODO[epic=Binds] This should only be set if having dms
-"Mod+B"."spawn-sh" = "dms ipc call bar toggle name \"Main Bar\""; #TODO[epic=Binds] This should only be set if having dms
+"Mod+B"."spawn-sh" = "dms ipc call bar toggle name \"Main Bar\"; dms ipc call bar toggle name \"Bar 2\""; #TODO[epic=Binds] This should only be set if having dms
 "Mod+Shift+B"."spawn-sh" = "dms ipc call bar toggle name \"Bar 2\""; #TODO[epic=Binds] This should only be set if having dms
 "Mod+L"."spawn-sh" = "dms ipc call lock lock"; #TODO[epic=Binds] This should only be set if having dms
 
@@ -178,28 +179,55 @@ let
       // lib.optionalAttrs (windowRules != [ ]) {
         window-rules = windowRules;
       }
-      // lib.optionalAttrs (rpi5Extra != "" || (userExtra.extraConfig or "") != "") {
+      // lib.optionalAttrs (extraConfigMerged != "") {
         extraConfig = extraConfigMerged;
       }
     );
 in
 {
   flake.homeManagerModules.desktopNiri =
-    { lib, pkgs, osConfig ? { }, ... }:
+    { config, lib, pkgs, osConfig ? { }, ... }:
     let
+      home = config.home.homeDirectory;
       niriOs = osConfig.chiasson.desktop.niri or { };
       niriEnabled = osConfig.chiasson.desktop.niri.enable or false;
       keyringEnabled = osConfig.chiasson.desktop.keyring.enable or false;
-      mergedSettings = mergeNiriSettings pkgs niriOs keyringEnabled;
+      dmsEnabled = (osConfig.chiasson.desktop.shell or null) == "dms";
+      dmsWindowRulesPath = "${home}/.config/niri/dms/windowrules.kdl";
+      # wrapper-modules emits quoted KDL (`"include" "…"`) which DMS's parser ignores.
+      # config.kdl is a store symlink, so a relative include would not resolve to the real
+      # ~/.config/niri/dms/windowrules.kdl that DMS writes at runtime.
+      dmsWindowRulesInclude = lib.optionalString dmsEnabled ''
+        include "${dmsWindowRulesPath}"
+      '';
+      baseMergedSettings = mergeNiriSettings pkgs niriOs keyringEnabled;
+      mergedSettings = lib.recursiveUpdate baseMergedSettings {
+        extraConfig = dmsWindowRulesInclude + (baseMergedSettings.extraConfig or "");
+      };
       niriConfigPkg = inputs.wrapper-modules.wrappers.niri.wrap {
         inherit pkgs;
         settings = mergedSettings;
+        # User-owned rules path is not available during the Nix build.
+        disableConfigValidation = dmsEnabled;
       };
     in
     {
-      config = lib.mkIf niriEnabled {
-        xdg.configFile."niri/config.kdl".source = "${niriConfigPkg}/niri-config.kdl";
-      };
+      config = lib.mkIf niriEnabled (lib.mkMerge [
+        {
+          xdg.configFile."niri/config.kdl".source = "${niriConfigPkg}/niri-config.kdl";
+        }
+        (lib.mkIf dmsEnabled {
+          # Seed empty rules file so niri can load the include before DMS first deploy.
+          home.activation.dmsNiriWindowRulesSeed = lib.hm.dag.entryAfter [ "writeBoundary" ] ''
+            rulesDir="$HOME/.config/niri/dms"
+            rulesFile="$rulesDir/windowrules.kdl"
+            mkdir -p "$rulesDir"
+            if [ ! -e "$rulesFile" ]; then
+              ${pkgs.coreutils}/bin/touch "$rulesFile"
+            fi
+          '';
+        })
+      ]);
     };
 
   flake.nixosModules.desktopNiri =