feat(location): add manual frequency option and optimize position loading

packages/utils/lib/src/duration_format.dart

@@ -1,4 +1,5 @@
 String formatSecondsCompact(int seconds) {
+  if (seconds < 0) return '';
   if (seconds >= 3600) return '${seconds ~/ 3600}h';
   if (seconds >= 60) return '${seconds ~/ 60}m';
   return '${seconds}s';