Use Exception#initialize hook for lazy loading

Load error enhancer gems on first exception creation by hooking
into Exception#initialize. This ensures gems are loaded before
detailed_message is called, so their prepended modules are
properly in the method chain. After loading, the overhead is
a single boolean check per exception creation.

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

Author: hsbt

gem_prelude.rb

@@ -36,14 +36,18 @@ def self.load
         warn "`syntax_suggest' was not loaded."
       end if defined?(SyntaxSuggest)
     end
+  end
 
-    def detailed_message(...)
-      return super if Ruby::DetailedError.loaded?
-      Ruby::DetailedError.load
-      # Re-dispatch to pick up the newly prepended methods from the gems
-      detailed_message(...)
+  # Load error enhancer gems on first exception creation.
+  # By hooking into initialize, gems are loaded before
+  # detailed_message is called, so their prepended modules
+  # are properly in the method chain.
+  module Ruby::DetailedError::Hook # :nodoc:
+    def initialize(...)
+      Ruby::DetailedError.load unless Ruby::DetailedError.loaded?
+      super
     end
   end
 
-  Exception.prepend(Ruby::DetailedError)
+  Exception.prepend(Ruby::DetailedError::Hook)
 end