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/LoadingDelegate.mc

@@ -0,0 +1,15 @@
+import Toybox.Lang;
+import Toybox.WatchUi;
+
+// Allows the user to cancel GPS acquisition by pressing BACK.
+class LoadingDelegate extends WatchUi.BehaviorDelegate {
+
+    function initialize() {
+        BehaviorDelegate.initialize();
+    }
+
+    function onBack() as Boolean {
+        WatchUi.popView(WatchUi.SLIDE_RIGHT);
+        return true;
+    }
+}