Fix ImageExample registration failure with async script loading

The commit ee80bc2 changed the main client-bundle to use async: true for
better performance, but left generated_component_packs_loading_strategy
set to :defer in the dummy app configuration. This caused a race condition
where:

1. Main bundle (async: true) executes immediately when downloaded
2. Auto-generated ImageExample pack (:defer) executes after page load
3. Main bundle tries to hydrate ImageExample before it's registered

Solution: Change generated_component_packs_loading_strategy from :defer
to :async to match the main bundle loading strategy and prevent the race
condition.

This aligns with the default behavior (async when Shakapacker >= 8.2.0)
and the documentation added in ee80bc2.

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

Co-Authored-By: Claude <noreply@anthropic.com>

Author: justin808

spec/dummy/Gemfile.lock

@@ -269,6 +269,8 @@ GEM
     rb-fsevent (0.11.2)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
+    rbs (3.9.5)
+      logger
     rdoc (6.14.2)
       erb
       psych (>= 4.0.0)
@@ -382,9 +384,6 @@ GEM
       actionpack (>= 6.0.0)
       activejob (>= 6.0.0)
       railties (>= 6.0.0)
-    turbolinks (5.2.1)
-      turbolinks-source (~> 5.2)
-    turbolinks-source (5.2.0)
     tzinfo (2.0.6)
       concurrent-ruby (~> 1.0)
     uglifier (4.2.0)
@@ -433,6 +432,7 @@ DEPENDENCIES
   pry-rescue
   puma (~> 6.0)
   rails (~> 7.1)
+  rbs
   react_on_rails!
   rspec-rails
   rspec-retry
@@ -449,7 +449,6 @@ DEPENDENCIES
   sprockets (~> 4.0)
   sqlite3 (~> 1.6)
   turbo-rails
-  turbolinks
   uglifier
   webdrivers (= 5.3.0)
 

spec/dummy/config/initializers/react_on_rails.rb

@@ -42,5 +42,5 @@ def self.adjust_props_for_client_side_hydration(component_name, props)
   config.components_subdirectory = "startup"
   config.auto_load_bundle = true
   config.immediate_hydration = false
-  config.generated_component_packs_loading_strategy = :defer
+  config.generated_component_packs_loading_strategy = :async
 end