Generic error handlers such as FactorioServer.handle() and the event
handler catch in Link only log err.stack, so the ajv errors attached to
an InvalidMessage were lost unless the catch site checked for the class
explicitly. Appending the errors to the stack in the constructor makes
every stack-logging handler show which field failed validation without
special casing each one.
Fixes#986
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
