feat: update backend OCR parser, web app, mobile app camera/preview UI, tests, and documentation with sample images

test/camera_location_test.dart

@@ -23,6 +23,7 @@ void main() {
       speedAccuracy: 1.0,
     );
     LocationService.mockDeterminator = () async => mockPos;
+    LocationService.mockStream = Stream.value(mockPos);
 
     // Create a dummy image file in temp directory
     final tempDir = Directory.systemTemp.createTempSync();
@@ -74,5 +75,6 @@ void main() {
       tempDir.deleteSync();
     } catch (_) {}
     LocationService.mockDeterminator = null;
+    LocationService.mockStream = null;
   });
 }