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.

systems/skip01.nix

@@ -6,13 +6,12 @@
 
   # Boot and kernel modules for Intel NUC
   boot.initrd.availableKernelModules = [ "xhci_pci" "ahci" "nvme" "usb_storage" "sd_mod" ];
-  boot.initrd.kernelModules = [ "i915" ]; # Intel integrated graphics
+  boot.initrd.kernelModules = [ ]; # No graphics drivers needed for headless
   boot.kernelModules = [ "kvm-intel" ]; # Intel virtualization support
   boot.extraModulePackages = [];
   
-  # Intel-specific kernel parameters
+  # Server-specific kernel parameters
   boot.kernelParams = [
-    "i915.enable_guc=2"  # Enable GuC and HuC for better power management
     "intel_iommu=on"     # Enable IOMMU for virtualization
   ];
 
@@ -20,18 +19,7 @@
 
   nixpkgs.hostPlatform = lib.mkDefault "x86_64-linux";
 
-  # Intel graphics support
-  hardware.opengl = {
-    enable = true;
-    driSupport = true;
-    driSupport32Bit = true;
-    extraPackages = with pkgs; [
-      intel-media-driver  # VAAPI driver for newer Intel GPUs
-      vaapiIntel         # VAAPI driver for older Intel GPUs
-      vaapiVdpau
-      libvdpau-va-gl
-    ];
-  };
+  # No graphics support needed for headless server
 
   # Power management optimized for server use
   powerManagement = {
@@ -61,7 +49,7 @@
     }
   ];
 
-  # Enable hardware monitoring
+  # Enable hardware monitoring (CLI only)
   hardware.sensor.iio.enable = true;
   
   # Network performance tuning for server use