fix: 修复特征提取失败(错误码81929)

问题: extractFaceFeature 返回错误码 81929 (MERR_FSDK_FACEFEATURE_FACEDATA)

根本原因: detectFaces 返回的人脸信息缺少 faceData 字段，
而虹软 SDK 的 extractFaceFeature 必须要有这个字段才能提取特征

修复:
- FaceEngineManager.convertFaceInfoToList: 添加返回 faceData
- ArcPlugin.handleExtractFaceFeature: 接收并传递 faceData 参数
- Dart API: extractFaceFeature 添加 faceData 参数
- example: 传递 faceData 到特征提取调用

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

lib/arc_platform_interface.dart

@@ -0,0 +1,147 @@
+import 'dart:typed_data';
+
+import 'package:plugin_platform_interface/plugin_platform_interface.dart';
+
+import 'arc_method_channel.dart';
+
+abstract class ArcPlatform extends PlatformInterface {
+  /// Constructs a ArcPlatform.
+  ArcPlatform() : super(token: _token);
+
+  static final Object _token = Object();
+
+  static ArcPlatform _instance = MethodChannelArc();
+
+  /// The default instance of [ArcPlatform] to use.
+  ///
+  /// Defaults to [MethodChannelArc].
+  static ArcPlatform get instance => _instance;
+
+  /// Platform-specific implementations should set this with their own
+  /// platform-specific class that extends [ArcPlatform] when
+  /// they register themselves.
+  static set instance(ArcPlatform instance) {
+    PlatformInterface.verifyToken(instance, _token);
+    _instance = instance;
+  }
+
+  /// 获取平台版本
+  Future<String?> getPlatformVersion() {
+    throw UnimplementedError('platformVersion() has not been implemented.');
+  }
+
+  /// 激活 SDK（在线激活）
+  /// [appId] 应用 ID（从虹软控制台获取）
+  /// [sdkKey] SDK 密钥（从虹软控制台获取）
+  /// [activeKey] 激活密钥
+  /// 返回包含 success, errorCode, message 的 Map
+  Future<Map<String, dynamic>?> activeOnline({
+    required String appId,
+    required String sdkKey,
+    required String activeKey,
+  }) {
+    throw UnimplementedError('activeOnline() has not been implemented.');
+  }
+
+  /// 初始化人脸识别引擎
+  /// [detectMode] 检测模式（0=VIDEO 视频流模式，1=IMAGE 图像模式）
+  /// [orient] 检测角度（0/90/180/270/360）
+  /// [maxFaceNum] 最大可检测人脸数量
+  /// [combinedMask] 功能组合掩码
+  /// 返回包含 success, errorCode, message 的 Map
+  Future<Map<String, dynamic>?> init({
+    int? detectMode,
+    int? orient,
+    int? maxFaceNum,
+    int? combinedMask,
+  }) {
+    throw UnimplementedError('init() has not been implemented.');
+  }
+
+  /// 检测人脸（同时进行 RGB 活体检测）
+  /// [data] NV21 格式的图像数据
+  /// [width] 图像宽度
+  /// [height] 图像高度
+  /// [format] 图像格式（2050=NV21）
+  /// 返回包含 success, errorCode, message, faceList, rgbLiveness, isRgbAlive 的 Map
+  /// rgbLiveness: -1=未知, 0=非真人, 1=真人
+  Future<Map<String, dynamic>?> detectFaces({
+    required Uint8List data,
+    required int width,
+    required int height,
+    int format = 2050,
+  }) {
+    throw UnimplementedError('detectFaces() has not been implemented.');
+  }
+
+  /// 提取人脸特征
+  /// [data] NV21 格式的图像数据
+  /// [width] 图像宽度
+  /// [height] 图像高度
+  /// [format] 图像格式（2050=NV21）
+  /// [rectLeft] 人脸框左边界
+  /// [rectTop] 人脸框上边界
+  /// [rectRight] 人脸框右边界
+  /// [rectBottom] 人脸框下边界
+  /// [faceOrientation] 人脸角度
+  /// [faceId] 人脸ID（从detectFaces获取）
+  /// [faceData] 人脸数据（从detectFaces获取，必需！这是虹软SDK进行特征提取的关键数据）
+  /// [extractType] 特征提取类型（0=注册, 1=识别）
+  /// [mask] 口罩状态（0=未佩戴, 1=已佩戴）
+  /// 返回包含 success, errorCode, message, featureData 的 Map
+  Future<Map<String, dynamic>?> extractFaceFeature({
+    required Uint8List data,
+    required int width,
+    required int height,
+    required int rectLeft,
+    required int rectTop,
+    required int rectRight,
+    required int rectBottom,
+    int format = 2050,
+    int faceOrientation = 0,
+    int faceId = -1,
+    Uint8List? faceData,
+    int extractType = 1,
+    int mask = 0,
+  }) {
+    throw UnimplementedError('extractFaceFeature() has not been implemented.');
+  }
+
+  /// 比对人脸特征
+  /// [featureData1] 第一个人脸特征数据
+  /// [featureData2] 第二个人脸特征数据
+  /// [compareModel] 比对模型（0=生活照, 1=证件照）
+  /// 返回包含 success, errorCode, message, similarity 的 Map
+  Future<Map<String, dynamic>?> compareFaceFeature({
+    required Uint8List featureData1,
+    required Uint8List featureData2,
+    int compareModel = 0,
+  }) {
+    throw UnimplementedError('compareFaceFeature() has not been implemented.');
+  }
+
+  /// 注册单张人脸特征到人脸库（用于1:N搜索）
+  /// [searchId] 唯一标识符（用于后续搜索匹配，建议使用用户ID）
+  /// [featureData] 人脸特征数据（从extractFaceFeature获取，建议使用extractType=0注册模式）
+  /// [faceTag] 附属信息（可选，如用户名、员工ID等）
+  /// 返回包含 success, errorCode, message 的 Map
+  Future<Map<String, dynamic>?> registerFaceFeature({
+    required int searchId,
+    required Uint8List featureData,
+    String? faceTag,
+  }) {
+    throw UnimplementedError('registerFaceFeature() has not been implemented.');
+  }
+
+  /// 批量注册人脸特征到人脸库（用于1:N搜索）
+  /// [faceList] 人脸列表，每项需包含：
+  ///            - searchId: 唯一标识符
+  ///            - featureData: 人脸特征数据
+  ///            - faceTag: 附属信息（可选）
+  /// 返回包含 success, errorCode, message 的 Map
+  Future<Map<String, dynamic>?> registerFaceFeatureBatch({
+    required List<Map<String, dynamic>> faceList,
+  }) {
+    throw UnimplementedError('registerFaceFeatureBatch() has not been implemented.');
+  }
+}