gnome: custom logo menu + dconf defaults

- Patch Logo Menu v38 to custom entries incl. Containers (DistroShelf)\n- Switch GNOME defaults to programs.dconf profile\n- Add desktop overrides for Thunar->Files and Ghostty->Terminal\n- Enable Thunar integration (gvfs/tumbler/xfconf) and add virt-manager tooling

modules/system/packages.nix

@@ -1,8 +1,39 @@
 { lib, pkgs, ... }:
 
-{
+let
+  # Override Thunar desktop entry to show as "Files".
+  thunarDesktopOverride = pkgs.makeDesktopItem {
+    name = "thunar";                     # same filename to shadow upstream entry
+    desktopName = "Files";
+    genericName = "File Manager";
+    tryExec = "thunar";
+    exec = "thunar %U";
+    icon = "org.xfce.thunar";
+    categories = [ "Utility" "FileManager" ];
+    mimeTypes = [ "inode/directory" ];
+    keywords = [ "folder" "manager" "explorer" "files" ];
+    startupNotify = true;
+    startupWMClass = "Thunar";
+    terminal = false;
+    comment = "Browse files";
+  };
+
+  # Override Ghostty desktop entry to show as "Terminal".
+  ghosttyDesktopOverride = pkgs.makeDesktopItem {
+    name = "com.mitchellh.ghostty";
+    desktopName = "Terminal";
+    genericName = "Terminal Emulator";
+    exec = "ghostty";
+    icon = "com.mitchellh.ghostty";
+    categories = [ "System" "TerminalEmulator" "Utility" ];
+    terminal = false;
+    comment = "Fast GPU-accelerated terminal";
+  };
+in {
   # Baseline system tools available everywhere; users run Home Manager standalone.
   config.environment.systemPackages = lib.mkAfter [
+    (lib.hiPrio thunarDesktopOverride)
+    (lib.hiPrio ghosttyDesktopOverride)
     pkgs.distrobox
     pkgs.distroshelf
     pkgs.dnsmasq
@@ -35,6 +66,9 @@
     pkgs.libnotify
     pkgs.micro
     pkgs.mission-center
+    pkgs.p7zip
     pkgs.podman-compose
+    pkgs.papirus-icon-theme
+    pkgs.xdg-utils
   ];
 }