Fix tap-to-rotate and GPS cancel crash

- Tap on non-selected icon rotates instead of opening, flag
  prevents onSelect from double-firing
- GpsService.stop() for clean cancellation
- LoadingView stops GPS on hide (BACK button)
- LoadingDelegate allows BACK to cancel GPS acquisition

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

source/GpsService.mc

@@ -60,6 +60,14 @@ class GpsService {
         }
     }
 
+    function stop() as Void {
+        if (_finished) { return; }
+        _finished = true;
+        _timer.stop();
+        _pollTimer.stop();
+        Position.enableLocationEvents(Position.LOCATION_DISABLE, method(:_onPosition));
+    }
+
     function _onTimeout() as Void {
         _finish(_bestFix);
     }