fix: make ocr segments json serializable

app.py

@@ -165,10 +165,11 @@ def ocr_and_parse(image: Image.Image) -> Dict[str, Any]:
         if not cleaned:
             continue
         lines.append(cleaned)
+        box_serializable = np.asarray(bbox, dtype=float).tolist()
         segments.append({
             "text": cleaned,
             "confidence": float(confidence),
-            "bbox": bbox,
+            "bbox": box_serializable,
         })
 
     raw_text = "\n".join(lines)