Refactor NixOS configuration: Move GUI apps to desktop modules and create headless config

- Move GUI applications from users/jsutter.nix to appropriate desktop modules:
  * office.nix: slack, signal-desktop
  * gaming.nix: discord, stremio
  * plasma.nix: arc-theme, pinentry, tigervnc
  * dev.nix: putty
  * media.nix (new): vlc, deluge

- Create systems/common-headless.nix for server configurations:
  * Remove GUI dependencies (Flatpak, XDG portals, fonts, graphics drivers)
  * Include only essential CLI tools and server packages
  * Disable X server completely

- Simplify skip01 configuration:
  * Remove Intel graphics drivers and OpenGL support
  * Use headless common configuration
  * Keep unified users/jsutter.nix (no split files)

- Update flake.nix to include new media.nix module in desktop systems

Result: Clean separation between desktop and headless configurations
with improved modularity and maintainability.

users/jsutter.nix

@@ -10,20 +10,11 @@
     hashedPassword = "$6$tvkhGd24G6pVOsWr$j8ZAqSnXPTGwMGmIulU5Puzqd4iKdu8eAMSFis/cPqTW6u2xGQMqPHH1W9IZwKSL6.nS7Jc/NR2VwpPosyXDH/";
     openssh.authorizedKeys.keys  = [ "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIBNVUh+RrcOSMRV6qysnsdPs5AyK8dSm4QhhnwgpikyI jsutter@symbiotrip.com" ];
     packages = with pkgs; [
-      vlc
-      pinentry
-      arc-theme
-      slack
-      direnv
-      deluge
-      pkgs-unstable.signal-desktop
-      putty
-      rpi-imager
-      discord
-      stremio
-      tigervnc
-      appimage-run
-      cloudflared
+      # Essential CLI tools and user utilities only
+      # GUI applications have been moved to appropriate desktop modules
+      direnv        # Development environment management
+      appimage-run  # System utility for AppImages
+      cloudflared   # Cloudflare tunnel CLI
     ];
   };