feat: Retain Last Finalized Image for ePaper After App Restart.

Author: Dhruv1797

lib/provider/image_loader.dart

@@ -1,30 +1,67 @@
+import 'dart:io';
 import 'dart:typed_data';
 
 import 'package:flutter/material.dart';
 import 'package:image/image.dart' as img;
 import 'package:image_cropper/image_cropper.dart';
 import 'package:image_picker/image_picker.dart';
+import 'package:path_provider/path_provider.dart';
 
 class ImageLoader extends ChangeNotifier {
   img.Image? image;
   final List<img.Image> processedImgs = List.empty(growable: true);
+  bool isLoading = false;
 
-  void pickImage({required int width, required int height}) async {
+  Future<bool> pickImage({required int width, required int height}) async {
     final ImagePicker picker = ImagePicker();
     final XFile? file = await picker.pickImage(source: ImageSource.gallery);
-    if (file == null) return;
+    if (file == null) return false;
 
     final croppedFile = await ImageCropper().cropImage(
       sourcePath: file.path,
-      aspectRatio:
-          CropAspectRatio(ratioX: width.toDouble(), ratioY: height.toDouble()),
+      aspectRatio: CropAspectRatio(
+        ratioX: width.toDouble(),
+        ratioY: height.toDouble(),
+      ),
     );
-    if (croppedFile == null) return;
+    if (croppedFile == null) return false;
 
     processedImgs.clear();
     image = await img.decodeImageFile(croppedFile.path);
 
     notifyListeners();
+    return true;
+  }
+
+  Future<void> saveFinalizedImageBytes(Uint8List bytes) async {
+    final dir = await getApplicationDocumentsDirectory();
+    final file = File('${dir.path}/last_finalized.png');
+    await file.writeAsBytes(bytes);
+  }
+
+  Future<void> loadFinalizedImage({
+    required int width,
+    required int height,
+  }) async {
+    isLoading = true;
+    notifyListeners();
+    
+    try {
+      final dir = await getApplicationDocumentsDirectory();
+      final file = File('${dir.path}/last_finalized.png');
+
+      if (await file.exists()) {
+        final bytes = await file.readAsBytes();
+        final decoded = img.decodeImage(bytes);
+        if (decoded != null) {
+          final resized = img.copyResize(decoded, width: width, height: height);
+          image = resized;
+        }
+      }
+    } finally {
+      isLoading = false;
+      notifyListeners();
+    }
   }
 
   Future<void> updateImage({