Update flake.lock and refine module settings

Bump revisions, hashes and timestamps in flake.lock for several inputs.

Simplify greetd configuration by using a direct default_session
assignment.
Restructure core stylix targets, adding a kmscon placeholder and
reorganizing limine options.
Remove empty GTK4 theme block, keeping only the dark‑theme flag in extra
config.
Extend home stylix: enable librewolf with extra options and add a GTK
target with colors, fonts, and flatpak support.

modules/home/gtk.nix

@@ -5,11 +5,6 @@
       package = pkgs.papirus-icon-theme;
     };
     gtk3.extraConfig.gtk-application-prefer-dark-theme = 1;
-    gtk4 = {
-      theme = null;
-      extraConfig = {
-        gtk-application-prefer-dark-theme = 1;
-      };
-    };
+    gtk4.extraConfig.gtk-application-prefer-dark-theme = 1;
   };
 }