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/macos/Flutter/GeneratedPluginRegistrant.swift

@@ -5,6 +5,7 @@
 import FlutterMacOS
 import Foundation
 
+import device_info_plus
 import flutter_secure_storage_macos
 import package_info_plus
 import screen_retriever_macos
@@ -13,6 +14,7 @@ import tray_manager
 import window_manager
 
 func RegisterGeneratedPlugins(registry: FlutterPluginRegistry) {
+  DeviceInfoPlusMacosPlugin.register(with: registry.registrar(forPlugin: "DeviceInfoPlusMacosPlugin"))
   FlutterSecureStoragePlugin.register(with: registry.registrar(forPlugin: "FlutterSecureStoragePlugin"))
   FPPPackageInfoPlusPlugin.register(with: registry.registrar(forPlugin: "FPPPackageInfoPlusPlugin"))
   ScreenRetrieverMacosPlugin.register(with: registry.registrar(forPlugin: "ScreenRetrieverMacosPlugin"))