feat: test user+plasma

hosts/common/features/Applications.nix

@@ -36,4 +36,5 @@
     '';
   };
   programs.steam.enable = true;
+  hardware.steam-hardware.enable = true;
 }

hosts/common/features/Desktop.nix

@@ -10,6 +10,7 @@
   # --- Display & window managers ---
   services.displayManager.sddm.enable = true;
   services.displayManager.sddm.wayland.enable = true;
+  services.desktopManager.plasma6.enable = true;
   programs.niri.enable = true;
   programs.skwd-wall.enable = true;
   programs.gamescope.enable = true;
@@ -28,5 +29,7 @@
     mako
     swaylock
     inputs.awww.packages.${pkgs.stdenv.hostPlatform.system}.awww
+    # --- KDE extras ---
+    kdePackages.karousel
   ];
 }