refactor setup script to use a variable for continuation flag handling

setup.sh

@@ -455,7 +455,8 @@ main() {
         git clone "$GIT_REPO" "$DOTFILES_DIR" || die "Failed to clone dotfiles repository"
     fi
 
-    if [ "$1" = "--continue" ]; then
+    CONTINUE=$1
+    if [ "$CONTINUE" = "--continue" ]; then
         log_info "Continuing setup..."
     else
         warning_prompt
@@ -463,7 +464,7 @@ main() {
         check_selinux
         install_nix
     fi
-    
+
     install_home_manager
     setup_symlinks