Add detection calibration evidence export

backend/README.md

@@ -389,6 +389,19 @@ with detection count, score, precision, recall, F1, mean IoU and false
 positive/negative counts. It is intended to tune confidence/IoU/model choices,
 not to add new inference behavior.
 
+To inspect the evidence behind a calibration run, export the persisted QA
+evidence bundle:
+
+```bash
+CALIBRATION_SUMMARY_PATH=/mnt/user/appdata/geointel/artifacts/detection-calibration/20260707T002103Z/calibration_summary.json \
+bash scripts/export_detection_calibration_evidence.sh http://192.168.10.150:1202
+```
+
+The bundle writes combined QA evidence GeoJSON plus a standalone HTML/SVG review
+artifact that separates matched detections, matched references, false positives
+and false negatives by role. It reads existing persisted `QualityCheck` evidence
+only and does not rerun inference.
+
 ### Run backend
 
 ```bash