refactor hostname preparation to check for existing hostname before NixOS verification

setup.sh

@@ -358,18 +358,19 @@ prepare_hostname() {
     local hostname
 
     # Only check for NixOS if hardware configuration is not found
-    if command -v nixos-version >/dev/null 2>&1; then
+    if [ -f "$hostname_file" ]; then
-        if [ -f "$hostname_file" ]; then
+        hostname=$(cat "$hostname_file")
-            hostname=$(cat "$hostname_file")
+        log_success "Hostname already found in $hostname_file. Using $hostname."
-            log_success "Hostname already found in $hostname_file. Using $hostname."
+        
-
+        if command -v nixos-version >/dev/null 2>&1; then
             if [ ! -f "$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..."
-            return
         fi
+
+        return
     fi
 
     # Ensure interactive input before hostname prompt