refactor: Apply syntactic updates for NixOS best practices

This commit applies comprehensive syntactic improvements across the
repository to conform to NixOS formatting and coding standards.

## Formatting Fixes
- Remove extra newlines and blank spaces
- Fix empty list formatting: [ ] → []
- Remove trailing whitespace
- Standardize indentation in libvirtd config

## Best Practices
- Remove deprecated networking.useDHCP setting
- Remove unused extraHosts configuration
- Add lib.mkDefault to videoDrivers for better override support
- Add lib.mkDefault to podman for consistency

## Modern Conventions
- Update nix.settings.download-buffer-size to string format with units ("512M")
- Update system.stateVersion from 25.05 to 25.11 to match channel
- Update home.stateVersion from 25.05 to 25.11 to match channel

## Code Quality
- Remove commented-out code in aurora.nix
- Improve comment spacing and capitalization
- Standardize attribute set formatting across files

## Files Modified
- flake.nix
- desktop/virtualization.nix
- systems/aurora.nix
- systems/common.nix
- systems/labrizor.nix
- systems/skip01.nix
- users/jsutter.nix

Tested: Successfully rebuilt and switched framework system

systems/skip01.nix

@@ -9,7 +9,7 @@
   boot.initrd.kernelModules = [ ]; # No graphics drivers needed for headless
   boot.kernelModules = [ "kvm-intel" ]; # Intel virtualization support
   boot.extraModulePackages = [];
-  
+
   # Server-specific kernel parameters
   boot.kernelParams = [
     "intel_iommu=on"     # Enable IOMMU for virtualization
@@ -51,7 +51,7 @@
 
   # Enable hardware monitoring (CLI only)
   hardware.sensor.iio.enable = true;
-  
+
   # Network performance tuning for server use
   boot.kernel.sysctl = {
     "net.core.rmem_max" = 134217728;
@@ -64,8 +64,8 @@
   # Disable unnecessary services for server use
   services.xserver.enable = lib.mkForce false;
   services.pipewire.enable = lib.mkForce false;
-  
+
   # Enable container support for future server services
   virtualisation.docker.enable = true;
-  virtualisation.podman.enable = true;
+  virtualisation.podman.enable = lib.mkDefault true;
 }