fixed model training

ANNOTATE/web/app.py

@@ -213,7 +213,7 @@ class AnnotationDashboard:
                         SELECT checkpoint_id, performance_metrics, timestamp, file_path
                         FROM checkpoint_metadata
                         WHERE model_name = ? AND is_active = TRUE
-                        ORDER BY performance_score DESC
+                        ORDER BY timestamp DESC
                         LIMIT 1
                     """, (model_name.lower(),))