Use Exception#detailed_message hook for lazy loading error enhancer gems

Replace direct gem loading with prepending an Exception::DetailedMessage
module that loads the gems on first detailed_message call, then removes
itself from the method chain to avoid double dispatch.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: hsbt

gem_prelude.rb

@@ -36,14 +36,16 @@ def self.load
         warn "`syntax_suggest' was not loaded."
       end if defined?(SyntaxSuggest)
     end
+  end
 
+  module Exception::DetailedMessage # :nodoc:
     def detailed_message(...)
-      return super if Ruby::DetailedError.loaded?
       Ruby::DetailedError.load
-      # Re-dispatch to pick up the newly prepended methods from the gems
+      # Remove this hook so subsequent calls go directly to
+      # the newly-prepended gem methods without double dispatch.
+      Exception::DetailedMessage.remove_method(:detailed_message)
       detailed_message(...)
     end
   end
-
-  Exception.prepend(Ruby::DetailedError)
+  Exception.prepend(Exception::DetailedMessage)
 end