Add automatic pack generation to bin/dev scripts

Updates both the dummy app and generator templates to automatically
run react_on_rails:generate_packs before starting development servers.

Changes:
- spec/dummy/bin/dev: Add pack generation to dummy app dev script
- lib/generators/react_on_rails/bin/dev: Update generator template
- lib/generators/react_on_rails/bin/dev-static: Update static generator template

Benefits:
- Developers no longer need to manually run rake react_on_rails:generate_packs
- Ensures generated packs are always up to date when starting development
- Provides clear feedback about pack generation process
- Fails fast with clear error message if pack generation fails

All bin/dev scripts now automatically:
1. Generate React on Rails packs with detailed feedback
2. Exit with error if pack generation fails
3. Start the development server only after successful pack generation

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

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

Author: justin808

lib/generators/react_on_rails/bin/dev

@@ -8,6 +8,16 @@ rescue Errno::ENOENT
 end
 
 def run(process)
+  # Generate React on Rails packs before starting development server
+  puts "📦 Generating React on Rails packs..."
+  system "bundle exec rake react_on_rails:generate_packs"
+  
+  unless $?.success?
+    puts "❌ Pack generation failed"
+    exit 1
+  end
+  
+  puts "🚀 Starting development server..."
   system "#{process} start -f Procfile.dev"
 rescue Errno::ENOENT
   warn <<~MSG

lib/generators/react_on_rails/bin/dev-static

@@ -8,6 +8,16 @@ rescue Errno::ENOENT
 end
 
 def run(process)
+  # Generate React on Rails packs before starting development server  
+  puts "📦 Generating React on Rails packs..."
+  system "bundle exec rake react_on_rails:generate_packs"
+  
+  unless $?.success?
+    puts "❌ Pack generation failed"
+    exit 1
+  end
+  
+  puts "🚀 Starting development server with static assets..."
   system "#{process} start -f Procfile.dev-static"
 rescue Errno::ENOENT
   warn <<~MSG

spec/dummy/bin/dev

@@ -6,4 +6,14 @@ then
   gem install foreman
 fi
 
+# Generate React on Rails packs before starting development server
+echo "📦 Generating React on Rails packs..."
+bundle exec rake react_on_rails:generate_packs
+
+if [ $? -ne 0 ]; then
+  echo "❌ Pack generation failed"
+  exit 1
+fi
+
+echo "🚀 Starting development server..."
 foreman start -f Procfile.dev