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/hosts/desktop-home-base.nix

@@ -80,7 +80,7 @@
                     enable = lib.mkDefault true;
                     swiftshareApiKeyFile = "/run/secrets/swiftshare/API_KEY"; #TODO[epic=sops] redo this by passing sops file output directly
                   };
-                  # WhiteSur GTK/icons, Phinger cursor, Qt via KDE platform theme; imports DMS matugen `dank-colors.css`.
+                  # WhiteSur GTK/icons, Phinger cursor, DMS matugen for GTK (+ qt6ct for Qt apps).
                   theming.enable = lib.mkDefault true;
                 };