feat(ui): re-enable MedSAM overlay rendering

app.py

@@ -695,9 +695,9 @@ def analyze_with_medsam(base_result, image, include_raw_masks=False):
         }
         log(f"analyze_with_medsam: segments={len(segmentations)}")
 
-        # Overlay disabled for stability
-        log("analyze_with_medsam: end (overlay disabled)")
-        return base_result, None
+        overlay_img = _overlay_masks_on_image(pil_img, masks_for_overlay) if masks_for_overlay else None
+        log("analyze_with_medsam: end")
+        return base_result, overlay_img
     except Exception:
         log("analyze_with_medsam: fatal error")
         traceback.print_exc()