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>

todo/todo.json

@@ -1,7 +1,7 @@
 {
   "meta": {
     "title": "feature+windows — 项目 TODO",
-    "updated_at": "2026-06-28T11:27:56.709Z"
+    "updated_at": "2026-06-28T13:19:24.300Z"
   },
   "seq": 12,
   "items": [
@@ -75,10 +75,10 @@
       "tags": [
         "后端"
       ],
-      "status": "done",
+      "status": "accepted",
       "created_at": "2026-06-27T23:37:24.980Z",
-      "done": false,
-      "completed_at": null,
+      "done": true,
+      "completed_at": "2026-06-28T13:19:24.207Z",
       "version": null
     },
     {
@@ -91,10 +91,10 @@
         "前端",
         "后端"
       ],
-      "status": "done",
+      "status": "accepted",
       "created_at": "2026-06-28T00:21:30.990Z",
-      "done": false,
-      "completed_at": null,
+      "done": true,
+      "completed_at": "2026-06-28T13:19:24.299Z",
       "version": null
     },
     {