Add generated_component_packs_loading_strategy to base initializer template

Per feedback, this setting should be in the base template (not Pro-only):

- Added to react_on_rails.rb.tt template with clear documentation
- Default is :defer (recommended for most apps)
- Documents that :async requires React on Rails Pro for better performance
- Explains the differences between :defer, :sync, and :async
- Prevents component registration race conditions with :defer default

This ensures new Rails apps get the configuration with sensible defaults.

Author: justin808

lib/generators/react_on_rails/templates/base/base/config/initializers/react_on_rails.rb.tt

@@ -64,4 +64,18 @@ ReactOnRails.configure do |config|
   # generated directory. default is false, you can pass option at the time of individual usage or update the default
   # in the following line
   config.auto_load_bundle = true
+
+  ################################################################################
+  # GENERATED COMPONENT PACKS LOADING STRATEGY
+  ################################################################################
+  # Configure how generated component packs are loaded in the browser.
+  # Options: :defer (default), :sync, :async
+  #
+  # - :defer (recommended for most apps): Scripts load in parallel but execute in order after HTML parsing
+  # - :sync: Scripts block HTML parsing (not recommended)
+  # - :async: Scripts load and execute as soon as available (requires React on Rails Pro for better performance)
+  #
+  # Default is :defer which provides good performance and prevents component registration race conditions.
+  # For React on Rails Pro users, :async can provide better performance by loading scripts asynchronously.
+  config.generated_component_packs_loading_strategy = :defer
 end