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/f8c96b9ba70d270e1df926aec2a1e154/web_plugin_registrant.dart

@@ -0,0 +1,18 @@
+// Flutter web plugin registrant file.
+//
+// Generated file. Do not edit.
+//
+
+// @dart = 2.13
+// ignore_for_file: type=lint
+
+import 'package:file_picker/src/platform/web/file_picker_web.dart';
+import 'package:shared_preferences_web/shared_preferences_web.dart';
+import 'package:flutter_web_plugins/flutter_web_plugins.dart';
+
+void registerPlugins([final Registrar? pluginRegistrar]) {
+  final Registrar registrar = pluginRegistrar ?? webPluginRegistrar;
+  FilePickerWeb.registerWith(registrar);
+  SharedPreferencesPlugin.registerWith(registrar);
+  registrar.registerMessageHandler();
+}