feat(arc): 添加虹软人脸识别插件基础功能

- 集成虹软 ArcSoft Face SDK，提供人脸检测、识别、活体检测功能
- 实现 Android 平台原生插件，包含 ArcPlugin 和 FaceEngineManager
- 添加完整的人脸错误码枚举（586个错误码），覆盖 SDK 所有错误情况
- 创建人脸信息数据模型 FaceInfo，封装检测结果和特征数据
- 配置 Android 权限和依赖，包括相机、存储、网络等必要权限
- 添加方法通道实现，连接 Flutter 层与原生层通信
- 配置项目基础文件，包含 .gitignore、分析选项和元数据配置
- 实现单元测试框架，包含 Dart 和 Java 层的基本测试用例
- 添加示例应用配置，验证插件集成和基本功能使用
- 提供详细的开发指导文档 CLAUDE.md，说明架构和 API 使用方法

example/integration_test/plugin_integration_test.dart

@@ -0,0 +1,25 @@
+// This is a basic Flutter integration test.
+//
+// Since integration tests run in a full Flutter application, they can interact
+// with the host side of a plugin implementation, unlike Dart unit tests.
+//
+// For more information about Flutter integration tests, please see
+// https://flutter.dev/to/integration-testing
+
+
+import 'package:flutter_test/flutter_test.dart';
+import 'package:integration_test/integration_test.dart';
+
+import 'package:arc/arc.dart';
+
+void main() {
+  IntegrationTestWidgetsFlutterBinding.ensureInitialized();
+
+  testWidgets('getPlatformVersion test', (WidgetTester tester) async {
+    final Arc plugin = Arc();
+    final String? version = await plugin.getPlatformVersion();
+    // The version string depends on the host platform running the test, so
+    // just assert that some non-empty string is returned.
+    expect(version?.isNotEmpty, true);
+  });
+}