feat(devices): P1 设备注册打通 —— 登录/注册即写 devices 表

后端:auth.Service 加 DeviceMeta + DeviceRegistrar 接口(consumer-side 解耦),
Login/Register 成功签发后 best-effort 注册设备(不强制设备上限,避免免费档重装
churn 锁死用户);handler 加 device 请求体;main 用 authDeviceRegistrar 适配
devices.Service 注入;normalizePlatform 加 linux。
客户端:新 device_identity.dart(SecureKV 接缝 + 稳定 UUIDv4 device_id 持久化 +
名称/平台/版本);弃用硬编码 'mac-001';auth_api login/register + connect 携带
device 元数据。加 uuid + device_info_plus 依赖。
测试:auth 设备注册(触发/best-effort/空 meta) + device_identity(生成/持久/
读失败不重生成/UUIDv4 形态);normalizePlatform linux=true。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

client/lib/services/auth_api.dart

@@ -61,11 +61,13 @@ class AuthApi {
     required String email,
     required String code,
     required String password,
+    Map<String, dynamic>? device,
   }) async {
     final resp = await _post('/v1/auth/register', {
       'email': email,
       'code': code,
       'password': password,
+      if (device != null) 'device': device,
     });
     if (resp.statusCode != 200 && resp.statusCode != 201) {
       _throwFromResponse(resp);
@@ -78,10 +80,12 @@ class AuthApi {
   Future<AuthTokens> login({
     required String email,
     required String password,
+    Map<String, dynamic>? device,
   }) async {
     final resp = await _post('/v1/auth/login', {
       'email': email,
       'password': password,
+      if (device != null) 'device': device,
     });
     if (resp.statusCode != 200) _throwFromResponse(resp);
     return AuthTokens.fromJson(jsonDecode(resp.body) as Map<String, dynamic>);