probably fixed blank page issue upon logout

frontend/src/Components/TimeRecorder.svelte

@@ -1,4 +1,5 @@
 <script>
+    import { onDestroy }     from 'svelte';
     import { useTinyRouter } from 'svelte-tiny-router';
 
     import { api }           from '../urls.svelte';
@@ -44,6 +45,10 @@
             interval = null;
         }
     });
+
+    onDestroy(() => {
+        if (interval) clearInterval(interval);
+    });
 </script>