fix: 隔离鸿蒙SDK特有类型，解决官方SDK编译冲突

- 新增 notification_init_stub.dart 桥接文件，隔离 OhosInitializationSettings
- 通知服务使用 buildNotificationInitSettings() 和 requestOhosNotificationPermission()
- HomeWidget 的 ohosName 参数通过 dynamic 调用隔离
- file_picker 升级到 ^11.0.0，API 从 FilePicker.platform.pickFiles 改为 FilePicker.pickFiles
- flutter_secure_storage 升级到 ^10.2.0
- macos/Podfile 部署目标从 10.15 升级到 13.0
- 更新 iOS_macOS_Developer_Guide.md v3

lib/editor/services/export/xycard_io_native.dart

@@ -12,7 +12,7 @@ import 'dart:typed_data';
 import 'package:file_picker/file_picker.dart';
 
 Future<Uint8List?> pickXycardFileImpl() async {
-  final result = await FilePicker.platform.pickFiles(
+  final result = await FilePicker.pickFiles(
     type: FileType.custom,
     allowedExtensions: ['xycard'],
   );

lib/editor/services/image/image_import_service.dart

@@ -19,7 +19,7 @@ class ImageImportService {
 
   static Future<Uint8List?> showImportSheet(BuildContext context) async {
     try {
-      final result = await FilePicker.platform.pickFiles(type: FileType.image);
+      final result = await FilePicker.pickFiles(type: FileType.image);
       if (result == null || result.files.isEmpty) return null;
       final file = result.files.first;
       if (file.bytes != null) return file.bytes;