feat(device): TX/RX 日志附加完整 JSON 字符串

test/device_protocol_test.dart

@@ -3,6 +3,7 @@ import 'dart:typed_data';
 
 import 'package:flutter_test/flutter_test.dart';
 import 'package:kuaishai2/features/device/models/device_state.dart';
+import 'package:kuaishai2/features/device/services/device_log.dart';
 import 'package:kuaishai2/features/device/services/device_message.dart';
 import 'package:kuaishai2/features/device/services/json_protocol.dart';
 import 'package:kuaishai2/features/device/services/task_payload.dart';
@@ -218,4 +219,38 @@ void main() {
       expect(s.infoStale, isTrue);
     });
   });
+
+  group('DeviceLog', () {
+    test('summarizeData 截断长字符串与多余键', () {
+      final data = {
+        'a': 1,
+        'b': 'short',
+        'c': 'x' * 200,
+        'd': [1, 2, 3],
+        'e': true,
+        'f': null,
+        'g': 'extra',
+        'h': 'extra2',
+        'i': 'extra3',
+      };
+      final summary = DeviceLog.summarizeData(data, maxKeys: 4);
+      expect(summary.contains('a=1'), isTrue);
+      expect(summary.contains('b="short"'), isTrue);
+      expect(summary.contains('…'), isTrue); // 长字符串被截断
+      expect(summary.contains('…'), isTrue);
+      expect(summary.contains(', ...'), isTrue); // 多余键被截断
+    });
+
+    test('summarizeData 空 Map / null 友好处理', () {
+      expect(DeviceLog.summarizeData(null), '{}');
+      expect(DeviceLog.summarizeData({}), '{}');
+    });
+
+    test('info / warn / severe 不抛异常', () {
+      // 仅验证调用不抛异常；dart:developer.log 在测试环境无可见输出
+      DeviceLog.info('hello');
+      DeviceLog.warn('warn', error: StateError('x'));
+      DeviceLog.severe('severe', error: 'err');
+    });
+  });
 }