feat: Add receipt import functionality with file upload and parsing

- Implemented receipt file upload in ImportRepository with multipart request handling.
- Created ParsedReceiptItem model for parsed receipt data.
- Added ReceiptImportTab for user interface to upload and review receipts.
- Updated ImportScreen to include the new ReceiptImportTab alongside RecipeImportTab.
- Introduced flutter_bootstrap.js and index.html for web app initialization.
- Added wimp.wasm and flutter.js for enhanced web performance and capabilities.

flutter/.dart_tool/flutter_build/dart_plugin_registrant.dart

@@ -6,9 +6,7 @@
 // @dart = 3.3
 
 import 'dart:io'; // flutter_ignore: dart_io_import.
-import 'package:file_picker/file_picker.dart' as file_picker;
 import 'package:shared_preferences_android/shared_preferences_android.dart' as shared_preferences_android;
-import 'package:file_picker/file_picker.dart' as file_picker;
 import 'package:shared_preferences_foundation/shared_preferences_foundation.dart' as shared_preferences_foundation;
 import 'package:file_picker/file_picker.dart' as file_picker;
 import 'package:path_provider_linux/path_provider_linux.dart' as path_provider_linux;
@@ -25,15 +23,6 @@ class _PluginRegistrant {
   @pragma('vm:entry-point')
   static void register() {
     if (Platform.isAndroid) {
-      try {
-        file_picker.FilePickerIO.registerWith();
-      } catch (err) {
-        print(
-          '`file_picker` threw an error: $err. '
-          'The app may not function as expected until you remove this plugin from pubspec.yaml'
-        );
-      }
-
       try {
         shared_preferences_android.SharedPreferencesAndroid.registerWith();
       } catch (err) {
@@ -44,15 +33,6 @@ class _PluginRegistrant {
       }
 
     } else if (Platform.isIOS) {
-      try {
-        file_picker.FilePickerIO.registerWith();
-      } catch (err) {
-        print(
-          '`file_picker` threw an error: $err. '
-          'The app may not function as expected until you remove this plugin from pubspec.yaml'
-        );
-      }
-
       try {
         shared_preferences_foundation.SharedPreferencesFoundation.registerWith();
       } catch (err) {