feat: 错误自动上报机制

- 后端：error_reports 表 + POST /api/v1/public/errors + GET /api/v1/admin/errors
- Flutter：ErrorReporter 单例，60s 去重，fire-and-forget，不影响用户
- main.dart：FlutterError 和 Zone 错误自动上报
- 打印异常：catch 块加 reportError，Windows 打印问题可自动采集堆栈

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

client/lib/core/errors/error_reporter.dart

@@ -0,0 +1,142 @@
+import 'dart:async';
+import 'dart:io' show Platform;
+
+import 'package:dio/dio.dart';
+import 'package:flutter/foundation.dart';
+import 'package:package_info_plus/package_info_plus.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+
+import '../config/app_config.dart';
+
+class ErrorType {
+  static const flutterError = 'flutter_error';
+  static const zoneError = 'zone_error';
+  static const caughtException = 'caught_exception';
+}
+
+class ErrorReporter {
+  ErrorReporter._();
+  static final ErrorReporter instance = ErrorReporter._();
+
+  static const _dedupWindowMs = 60 * 1000;
+  static const _maxStackLength = 3000;
+
+  final Map<String, int> _recentMessages = {};
+  Dio? _dio;
+  String? _cachedVersion;
+
+  Dio get _client {
+    _dio ??= Dio(BaseOptions(
+      baseUrl: AppConfig.apiBaseUrl,
+      connectTimeout: const Duration(seconds: 5),
+      receiveTimeout: const Duration(seconds: 5),
+    ));
+    return _dio!;
+  }
+
+  Future<String> _getVersion() async {
+    if (_cachedVersion != null) return _cachedVersion!;
+    try {
+      final info = await PackageInfo.fromPlatform();
+      _cachedVersion = info.version;
+    } catch (_) {
+      _cachedVersion = 'unknown';
+    }
+    return _cachedVersion!;
+  }
+
+  String _getPlatform() {
+    if (kIsWeb) return 'web';
+    try {
+      if (Platform.isIOS) return 'ios';
+      if (Platform.isAndroid) return 'android';
+      if (Platform.isMacOS) return 'macos';
+      if (Platform.isWindows) return 'windows';
+      if (Platform.isLinux) return 'linux';
+    } catch (_) {}
+    return 'unknown';
+  }
+
+  Future<Map<String, dynamic>> _getUserFields() async {
+    try {
+      final prefs = await SharedPreferences.getInstance();
+      return {
+        'username': prefs.getString('username') ?? '',
+        'shop_id': int.tryParse(prefs.getString('shop_id') ?? '') ?? 0,
+        'shop_no': prefs.getString('shop_no') ?? '',
+        'role': prefs.getString('role') ?? '',
+      };
+    } catch (_) {
+      return {'username': '', 'shop_id': 0, 'shop_no': '', 'role': ''};
+    }
+  }
+
+  bool _isDuplicate(String message) {
+    final now = DateTime.now().millisecondsSinceEpoch;
+    final lastTime = _recentMessages[message];
+    if (lastTime != null && now - lastTime < _dedupWindowMs) return true;
+    _recentMessages[message] = now;
+    if (_recentMessages.length > 100) {
+      _recentMessages.removeWhere((_, t) => now - t >= _dedupWindowMs);
+    }
+    return false;
+  }
+
+  void report({
+    required String errorType,
+    required String errorMsg,
+    StackTrace? stackTrace,
+  }) {
+    if (_isDuplicate(errorMsg)) return;
+    unawaited(_doReport(
+      errorType: errorType,
+      errorMsg: errorMsg,
+      stackTrace: stackTrace,
+    ));
+  }
+
+  Future<void> _doReport({
+    required String errorType,
+    required String errorMsg,
+    StackTrace? stackTrace,
+  }) async {
+    try {
+      final version = await _getVersion();
+      final userFields = await _getUserFields();
+
+      String? stack;
+      if (stackTrace != null) {
+        final raw = stackTrace.toString();
+        stack = raw.length > _maxStackLength ? raw.substring(0, _maxStackLength) : raw;
+      }
+
+      await _client.post('/public/errors', data: {
+        'error_type': errorType,
+        'app_version': version,
+        'platform': _getPlatform(),
+        'username': userFields['username'],
+        'shop_id': userFields['shop_id'],
+        'shop_no': userFields['shop_no'],
+        'role': userFields['role'],
+        'error_msg': errorMsg,
+        'stack_trace': stack ?? '',
+        'occurred_at': DateTime.now().millisecondsSinceEpoch,
+      });
+    } catch (_) {
+      // 上报失败静默处理，不影响用户
+    }
+  }
+}
+
+/// 便捷顶层函数，供 catch 块一行调用
+void reportError(
+  Object error,
+  StackTrace? stack, {
+  String errorType = ErrorType.caughtException,
+}) {
+  ErrorReporter.instance.report(
+    errorType: errorType,
+    errorMsg: error.toString(),
+    stackTrace: stack,
+  );
+}

client/lib/core/utils/print_util_stub.dart

@@ -1,4 +1,5 @@
 import 'package:flutter/services.dart';
+import '../errors/error_reporter.dart';
 import 'package:pdf/pdf.dart';
 import 'package:pdf/widgets.dart' as pw;
 import 'package:printing/printing.dart';
@@ -191,7 +192,8 @@ Future<void> printProductLabelImpl({
 
   try {
     await Printing.layoutPdf(onLayout: (_) async => doc.save());
-  } catch (e) {
+  } catch (e, st) {
+    reportError(e, st);
     throw Exception('打印失败，请检查打印机连接和驱动是否正常。\n详情：$e');
   }
 }
@@ -430,7 +432,8 @@ Future<void> printStockInOrderImpl(StockInOrder order) async {
   ));
   try {
     await Printing.layoutPdf(onLayout: (_) async => doc.save());
-  } catch (e) {
+  } catch (e, st) {
+    reportError(e, st);
     throw Exception('打印失败，请检查打印机连接和驱动是否正常。\n详情：$e');
   }
 }
@@ -484,7 +487,8 @@ Future<void> printStockOutOrderImpl(StockOutOrder order) async {
   ));
   try {
     await Printing.layoutPdf(onLayout: (_) async => doc.save());
-  } catch (e) {
+  } catch (e, st) {
+    reportError(e, st);
     throw Exception('打印失败，请检查打印机连接和驱动是否正常。\n详情：$e');
   }
 }

client/lib/main.dart

@@ -4,6 +4,7 @@ import 'package:flutter_localizations/flutter_localizations.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:flutter_web_plugins/url_strategy.dart';
 import 'core/auth/auth_state.dart';
+import 'core/errors/error_reporter.dart';
 import 'core/router/app_router.dart';
 import 'core/theme/app_theme.dart';
 import 'providers/connectivity_provider.dart';
@@ -15,6 +16,11 @@ void main() {
     debugPrint('═══ FlutterError ════════════════════════════');
     debugPrint(details.exceptionAsString());
     debugPrint(details.stack.toString());
+    ErrorReporter.instance.report(
+      errorType: ErrorType.flutterError,
+      errorMsg: details.exceptionAsString(),
+      stackTrace: details.stack,
+    );
   };
 
   runZonedGuarded(
@@ -23,6 +29,11 @@ void main() {
       debugPrint('═══ Zone Error ═══════════════════════════════');
       debugPrint(error.toString());
       debugPrint(stack.toString());
+      ErrorReporter.instance.report(
+        errorType: ErrorType.zoneError,
+        errorMsg: error.toString(),
+        stackTrace: stack,
+      );
     },
   );
 }