fixxed template error

app/__init__.py

@@ -21,6 +21,13 @@ def create_app():
                 template_folder='../templates',  # ← Root/templates statt app/templates
                 static_folder='../static')       # ← Root/static
 
+    from datetime import timedelta
+
+    def timedelta_filter(td):
+        return str(td)  # oder td.total_seconds() als Zahl
+
+    app.jinja_env.filters['timedelta'] = timedelta_filter
+
     # Config laden
     app.config.from_object('config.Config')