Use TracePoint(:raise) for lazy loading error enhancer gems

Load error enhancer gems on first exception raise using
TracePoint(:raise). The TracePoint is disabled after first
invocation, so there is zero overhead after loading.

Rescue ThreadError since require can't be called from trap
context (e.g., exit inside a signal handler).

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?
+  # Load error enhancer gems on first exception raise.
+  # TracePoint is disabled after first invocation, so there
+  # is zero overhead after loading.
+  trace = TracePoint.new(:raise) do
+    trace.disable
+    begin
       Ruby::DetailedError.load
-      # Re-dispatch to pick up the newly prepended methods from the gems
-      detailed_message(...)
+    rescue ThreadError
+      # require can't be called from trap context
     end
   end
-
-  Exception.prepend(Ruby::DetailedError)
+  trace.enable
 end