Add proper spec_helper require to ReactOnRails::Dev specs

Add relative require_relative '../spec_helper' to properly load the
ReactOnRails module and test configuration for Dev specs.

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

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

Author: justin808

spec/react_on_rails/dev/file_manager_spec.rb

@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require_relative "../spec_helper"
+
 RSpec.describe ReactOnRails::Dev::FileManager do
   # Suppress stdout/stderr during tests
   before(:all) do

spec/react_on_rails/dev/pack_generator_spec.rb

@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require_relative "../spec_helper"
+
 RSpec.describe ReactOnRails::Dev::PackGenerator do
   # Suppress stdout/stderr during tests
   before(:all) do

spec/react_on_rails/dev/process_manager_spec.rb

@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require_relative "../spec_helper"
+
 RSpec.describe ReactOnRails::Dev::ProcessManager do
   # Suppress stdout/stderr during tests
   before(:all) do

spec/react_on_rails/dev/server_manager_spec.rb

@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require_relative "../spec_helper"
+
 RSpec.describe ReactOnRails::Dev::ServerManager do
   # Suppress stdout/stderr during tests
   before(:all) do