fix setup script to ensure SELinux config writes correctly and clean up whitespace

setup.sh

@@ -366,7 +366,7 @@ prepare_hostname() {
             if [ ! -f "$DOTFILES_DIR/config/nixos/hardware/$hostname.nix" ]; then
                 die "No hardware configuration found for $hostname. Please create a hardware configuration for this machine."
             fi
-            
+
             log_success "Hardware configuration found for $hostname. Continuing setup..."
         fi
 
@@ -427,7 +427,7 @@ check_selinux() {
     if [ "$(getenforce)" = "Enforcing" ]; then
         log_warning "SELinux is enabled. Adjusting SELinux to permissive mode..."
         sudo setenforce Permissive || die "Failed to disable SELinux"
-        tee /etc/selinux/config <<EOF
+        sudo tee /etc/selinux/config << EOF > /dev/null || die "Failed to write to /etc/selinux/config"
 SELINUX=permissive
 SELINUXTYPE=targeted
 EOF