Mitigates the recurring test_script/validator_test_script narration issue
(100% repro across 3 tasks, 6 nodes): the existing compile-error feedback
buries its "not a narrative description" note under raw tracebacks, which
wasn't enough to stop the model repeating narrative output on retry. Adds
_NARRATION_RETRY_HINT as a separate, directive feedback item alongside the
compiler detail. See docs/todo/validator-test-script-narrative-output-issue.md
§6-7 for the full root-cause analysis and rationale.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
