feat(device): 实现下位机 JSON 协议（data model 对齐）

按 docs/下位机交互数据模型.md 重构串口协议层：

协议层
- 新增 DeviceMessage 模型，对应 message_id/type/ack/need_ack/data
- 新增 JsonProtocolService，4 字节大端长度前缀 + UTF-8 JSON 帧
- 删除原二进制协议（serial_protocol.dart）

服务层
- 新增 DeviceMessageService，集中收发并按 type 分发
- 重写 SerialRunner 为 JsonSerialRunner，使用 create_task/control 消息

数据模型
- DeviceState 增加 doorStatus/lightStatus/taskStatus/lastInfoAt
- 新增 DeviceInfoNotifier 订阅 device_info 上行
- 灯光按钮接通 light_control 消息

测试
- 新增 device_protocol_test.dart（14 用例）
- 修复 models_test.dart 残留的 Step mixSpeed/blowSpeed 错误

lib/features/home/widgets/status_bar.dart

@@ -1,30 +1,28 @@
 import 'dart:async';
 import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
 import '../../../core/localization/app_localizations.dart';
 import '../../../core/theme/app_theme.dart';
 import '../../../shared/widgets/status_indicator.dart';
+import '../../device/providers/device_info_provider.dart';
 
 /// 状态栏组件 - 明亮工业风格
-/// 显示设备名称、实时时钟、系统状态、照明控制、瓷套棒状态
-class StatusBar extends StatefulWidget {
+/// 显示设备名称、实时时钟、系统状态、照明控制
+class StatusBar extends ConsumerStatefulWidget {
   final bool isRunning;
-  final bool lightOn;
   final VoidCallback? onLightToggle;
-  final bool ceramicSleeveInstalled;
 
   const StatusBar({
     super.key,
     this.isRunning = false,
-    this.lightOn = false,
     this.onLightToggle,
-    this.ceramicSleeveInstalled = false,
   });
 
   @override
-  State<StatusBar> createState() => _StatusBarState();
+  ConsumerState<StatusBar> createState() => _StatusBarState();
 }
 
-class _StatusBarState extends State<StatusBar> {
+class _StatusBarState extends ConsumerState<StatusBar> {
   String _currentTime = '';
   Timer? _timer;
 
@@ -51,9 +49,15 @@ class _StatusBarState extends State<StatusBar> {
 
   String _twoDigits(int n) => n.toString().padLeft(2, '0');
 
+  Future<void> _onLightTap() async {
+    widget.onLightToggle?.call();
+    await ref.read(deviceInfoProvider.notifier).toggleLight();
+  }
+
   @override
   Widget build(BuildContext context) {
     final l10n = AppLocalizations.of(context);
+    final deviceInfo = ref.watch(deviceInfoProvider);
 
     return Container(
       height: 56,
@@ -86,9 +90,10 @@ class _StatusBarState extends State<StatusBar> {
             ],
           ),
           const Spacer(),
-          _LightToggleButton(isOn: widget.lightOn, onTap: widget.onLightToggle),
-          const SizedBox(width: 16),
-          _CeramicSleeveStatus(installed: widget.ceramicSleeveInstalled),
+          _LightToggleButton(
+            isOn: deviceInfo.lightingOn,
+            onTap: _onLightTap,
+          ),
           const SizedBox(width: 20),
           StatusIndicator(
             text: widget.isRunning
@@ -114,36 +119,6 @@ class _StatusBarState extends State<StatusBar> {
   }
 }
 
-class _CeramicSleeveStatus extends StatelessWidget {
-  final bool installed;
-  const _CeramicSleeveStatus({required this.installed});
-
-  @override
-  Widget build(BuildContext context) {
-    return Row(
-      mainAxisSize: MainAxisSize.min,
-      children: [
-        Container(
-          width: 8,
-          height: 8,
-          decoration: BoxDecoration(
-            shape: BoxShape.circle,
-            color: installed ? Colors.greenAccent : Colors.redAccent,
-          ),
-        ),
-        const SizedBox(width: 6),
-        Text(
-          installed ? '瓷套棒: 已安装' : '瓷套棒: 未安装',
-          style: TextStyle(
-            color: Colors.white.withValues(alpha: 0.9),
-            fontSize: 12,
-          ),
-        ),
-      ],
-    );
-  }
-}
-
 class _LightToggleButton extends StatelessWidget {
   final bool isOn;
   final VoidCallback? onTap;