a0d93d7f6d
- Update gps_data_manager.dart: import ProcessedGpsData from models/, use GpsConfig constants, replace all print() with Logger calls - Update gps_service.dart: use GpsConfig.VALID_HEADING_MIN/MAX for heading validation - Update main.dart: import from config/, models/, replace all customDebugPrint() and print() with Logger, use TimingConfig/OverlayConfig constants, convert overlay IPC to OverlayMessage typed class - Delete customDebugPrint() function definition - Delete lib/speed_units.dart and lib/color_themes.dart (moved to config/) - Zero analyzer errors, zero bare print() calls remaining