# Codex Pass 11 — QA/QC Foundation

## Goal

Implement foundational geometry comparison utilities.

## Must implement

- IoU utility for polygons;
- overlap-based matching strategy;
- precision/recall/F1 calculation for matched objects;
- tests for perfect match, partial match, no match, invalid geometry;
- docs update if thresholds are chosen.

## Must not implement

- live GRB integration unless already implemented safely;
- unclear thresholds without documentation.

## Output

Use `docs/M6_FINAL_HANDOFF_TEMPLATE.md`.