docs: add test plan for labeler report stage
Human verification plan generated after Phase 8 completion. All 38
acceptance criteria (AC1.1–AC8.4) are automated; this plan covers
quality-of-life visual checks, real-labeler end-to-end verification,
and the release-gate pollution-avoidance URL replacement.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
authored by