feat: implement GpsDataManager architecture with modular design

- Add GpsDataManager singleton service for centralized GPS data processing
- Refactor main app to use processed GPS data streams instead of raw position data
- Add haptic feedback to all main UI tap interactions (theme, unit, navigation)
- Implement faster GPS update frequency (500ms timeLimit in LocationSettings)
- Clean up verbose debug logging while preserving essential error logs
- Remove unused debug variables and imports
- Preserve existing background survival mechanisms and overlay lifecycle
- Add temporary GPS simulation while resolving geolocator engine conflicts

Architecture improvements:
- Clean data flow: GPS Hardware → GpsDataManager → Main App → Overlay
- Single source of truth for processed GPS data in manager
- Separation of concerns: GPS logic isolated from UI components
- Foundation ready for intelligent caching logic implementation

Technical notes:
- GPS engine conflict detected, temporarily using simulation data
- All functionality tested and working with test data
- Real GPS integration pending engine conflict resolution

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

lib/gps_service.dart

@@ -10,6 +10,7 @@ class GpsService {
       locationSettings: const LocationSettings(
         accuracy: LocationAccuracy.bestForNavigation,
         distanceFilter: 0,
+        timeLimit: Duration(milliseconds: 500), // Force updates every 500ms for faster GPS refresh
       ),
     );
   }