Fix Ruby 3.4 compatibility issue with method resolution in Configuration

Resolves NameError when calling ensure_webpack_generated_files_exists in Ruby 3.4.7.

The issue occurred because Ruby 3.4 is stricter about distinguishing between local
variables and method calls. When parameter names in the initialize method
(rsc_bundle_js_file, react_client_manifest_file, react_server_client_manifest_file)
shadowed the attr_accessor methods, Ruby 3.4's parser interpreted bare method calls
as undefined local variables.

Solution: Use public_send(:method_name) to explicitly call the accessor methods,
removing ambiguity for the Ruby 3.4 parser.

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

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

Author: justin808

lib/react_on_rails/configuration.rb

@@ -325,9 +325,9 @@ def ensure_webpack_generated_files_exists
       all_required_files = [
         "manifest.json",
         server_bundle_js_file,
-        rsc_bundle_js_file,
-        react_client_manifest_file,
-        react_server_client_manifest_file
+        public_send(:rsc_bundle_js_file),
+        public_send(:react_client_manifest_file),
+        public_send(:react_server_client_manifest_file)
       ].compact_blank
 
       if webpack_generated_files.empty?