Remove dead code from run_rake_task_directly method

Remove unreachable Rails environment loading code that was guarded by
'unless defined?(Rails)'. This guard is dead code because:

1. run_rake_task_directly is only called when rails_available? is true
2. rails_available? explicitly checks defined?(Rails) and returns false
   if Rails is not defined
3. Therefore Rails is always defined when this method executes

The removed line attempted to load config/environment using Dir.pwd,
which was both unreachable and used the wrong path resolution method.
Since Rails is guaranteed to be available in this context, we can rely
on Rails.application.load_tasks directly.

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

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

Author: justin808

lib/react_on_rails/dev/pack_generator.rb

@@ -45,9 +45,6 @@ def rails_available?
         def run_rake_task_directly(silent: false)
           require "rake"
 
-          # Load Rails environment if not already loaded
-          require File.expand_path("config/environment", Dir.pwd) unless defined?(Rails)
-
           # Load tasks only if not already loaded (don't clear all tasks)
           Rails.application.load_tasks unless Rake::Task.task_defined?("react_on_rails:generate_packs")