common: enable flakes, drop duplicate host imports, import quickshell

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

common.nix

@@ -3,14 +3,12 @@
 
 {
   imports = [
-    # Hosts #
-    ./hosts/FredOS-Gaming.nix
-    ./hosts/FredOS-Macbook.nix
-    ./hosts/FredOS-Mediaserver.nix
-    
+    # Host modules are imported per-host by mkHost in flake.nix.
+
     # Generic settings #
     ./settings/desktop.nix
     ./settings/hyprland.nix
+    ./settings/quickshell.nix
     ./settings/locale.nix
     ./settings/audio.nix
     ./settings/users.nix
@@ -89,6 +87,10 @@
   # Allow unfree packages
   nixpkgs.config.allowUnfree = true;
 
+  # Flakes — nixos-rebuild self-enables these, but plain `nix eval` /
+  # `nix flake check` on the hosts need them too.
+  nix.settings.experimental-features = [ "nix-command" "flakes" ];
+
   # Enable network-manager
   networking.networkmanager.enable = true;