Polish configuration and improve code clarity

## Changes

### RuboCop Configuration
- Exclude bin/* shell scripts from RuboCop checks

### Configuration Improvements
- Fix error message wording in configuration.rb (prefer :defer over :sync)
- Add explanatory comment in context.ts about TypeScript var requirement
- Improve ESLint config formatting (export at top, add deprecation disable)
- Add clarifying comment in helper spec about defer default strategy

These are small polish changes that improve code clarity and fix minor inconsistencies.

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

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

Author: justin808

.rubocop.yml

@@ -25,6 +25,7 @@ AllCops:
     - '**/node_modules/**/*'
     - '**/public/**/*'
     - '**/tmp/**/*'
+    - 'bin/*'  # Shell scripts
     - 'coverage/**/*'
     - 'gen-examples/examples/**/*'
     - 'node_modules/**/*'

eslint.config.ts

@@ -16,7 +16,8 @@ const compat = new FlatCompat({
   allConfig: js.configs.all,
 });
 
-const config = tsEslint.config([
+// eslint-disable-next-line @typescript-eslint/no-deprecated
+export default tsEslint.config([
   // eslint-disable-next-line @typescript-eslint/no-unsafe-argument, @typescript-eslint/no-unsafe-call, @typescript-eslint/no-unsafe-member-access
   includeIgnoreFile(path.resolve(__dirname, '.gitignore')),
   globalIgnores([
@@ -266,5 +267,3 @@ const config = tsEslint.config([
   // https://github.com/prettier/eslint-plugin-prettier?tab=readme-ov-file#configuration-new-eslintconfigjs
   prettierRecommended,
 ]);
-
-export default config;

lib/react_on_rails/configuration.rb

@@ -172,8 +172,8 @@ def validate_generated_component_packs_loading_strategy
 
       msg = <<~MSG
         ReactOnRails: Your current version of shakapacker \
-        does not support async script loading,  which may cause performance issues. Please either:
-        1. Use :sync or :defer loading strategy instead of :async
+        does not support async script loading. Please either:
+        1. Use :defer or :sync loading strategy instead of :async
         2. Upgrade to Shakapacker v8.2.0 or above to enable async script loading
       MSG
       if generated_component_packs_loading_strategy.nil?

packages/react-on-rails/src/context.ts

@@ -1,10 +1,11 @@
 import type { ReactOnRailsInternal, RailsContext } from './types/index.ts';
 
 declare global {
-  /* eslint-disable no-var,vars-on-top,no-underscore-dangle */
+  // TypeScript requires 'var' (not 'let') in 'declare global' for proper global scope augmentation across modules
+  /* eslint-disable no-underscore-dangle, vars-on-top */
   var ReactOnRails: ReactOnRailsInternal | undefined;
   var __REACT_ON_RAILS_EVENT_HANDLERS_RAN_ONCE__: boolean;
-  /* eslint-enable no-var,vars-on-top,no-underscore-dangle */
+  /* eslint-enable no-underscore-dangle, vars-on-top */
 }
 
 let currentRailsContext: RailsContext | null = null;

spec/dummy/spec/helpers/react_on_rails_helper_spec.rb

@@ -77,6 +77,8 @@ def self.pro_attribution_comment
       allow(helper).to receive(:append_stylesheet_pack_tag)
       expect { helper.load_pack_for_generated_component("component_name", render_options) }.not_to raise_error
 
+      # Default loading strategy is now always :defer to prevent race conditions
+      # between component registration and hydration, regardless of async support
       expect(helper).to have_received(:append_javascript_pack_tag).with("generated/component_name", { defer: true })
       expect(helper).to have_received(:append_stylesheet_pack_tag).with("generated/component_name")
     end