fix(framework): include shared desktop applications

- Import the desktop applications module on Framework
- Update module and README descriptions to cover all hosts

modules/desktop-apps.nix

@@ -1,6 +1,6 @@
 { pkgs, ... }:
 {
-  # Shared desktop applications; imported by the two ThinkPads.
+  # Shared desktop applications for all three hosts.
   environment.systemPackages = with pkgs; [
     bitwarden-desktop
     brave