enhance setup script to support continuation of installation process

setup.sh

@@ -301,7 +301,7 @@ install_nix() {
     fi
 
     log_success "Nix has been installed. We're reinvoking the script to continue setup."
-    curl -L https://df.mvl.sh | bash
+    curl -L https://df.mvl.sh | bash -s - -c
     exit 0
 }
 
@@ -446,6 +446,12 @@ main() {
         exit 0
     fi
 
+    # Check if this is a continuation -c flag
+    if [ "$1" = "-c" ]; then
+        log_info "Continuing setup..."
+        CONTINUATION=true
+    fi
+
     # Check prerequisites
     check_prerequisites
 
@@ -456,10 +462,13 @@ main() {
     fi
 
     # Run setup steps
-    warning_prompt
-    prepare_hostname
-    check_selinux
-    install_nix
+    if [ "$CONTINUATION" != "true" ]; then
+        warning_prompt
+        prepare_hostname
+        check_selinux
+        install_nix
+    fi
+
     install_home_manager
     setup_symlinks