Fix RuboCop violations in bin/dev template

- Convert multi-line unless to modifier form
- Add required trailing newline
- All linting now passes clean

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

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

Author: justin808

lib/generators/react_on_rails/templates/base/base/bin/dev

@@ -29,8 +29,6 @@ DEFAULT_ROUTE = "hello_world"
 # Main execution
 # Add the default route to ARGV if no --route option is provided
 argv_with_defaults = ARGV.dup
-unless argv_with_defaults.any? { |arg| arg.start_with?("--route") }
-  argv_with_defaults.push("--route", DEFAULT_ROUTE)
-end
+argv_with_defaults.push("--route", DEFAULT_ROUTE) unless argv_with_defaults.any? { |arg| arg.start_with?("--route") }
 
 ReactOnRails::Dev::ServerManager.run_from_command_line(argv_with_defaults)