perf: Optimize add_react_on_rails_package to eliminate redundant array conversions

Address Justin's minor optimization suggestion:
- Use add_js_dependencies_batch instead of add_js_dependency for single package
- Work with arrays consistently throughout the method flow
- Eliminates unnecessary string→array→string conversions
- Maintains identical functionality with improved efficiency

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: 2 people

lib/generators/react_on_rails/js_dependency_manager.rb

@@ -76,15 +76,17 @@ def add_react_on_rails_package
                                "react-on-rails"
                              end
 
+        packages_array = [react_on_rails_pkg]
+
         puts "Installing React on Rails package..."
-        if add_js_dependency(react_on_rails_pkg)
+        if add_js_dependencies_batch(packages_array)
           @added_dependencies_to_package_json = true
         else
           # Fallback to direct npm install
           puts "Using direct npm commands as fallback"
-          success = system("npm", "install", react_on_rails_pkg)
+          success = system("npm", "install", *packages_array)
           @ran_direct_installs = true if success
-          handle_npm_failure("react-on-rails package", [react_on_rails_pkg]) unless success
+          handle_npm_failure("react-on-rails package", packages_array) unless success
         end
       end