fix(auth): stop parsing logout response body (avoids ZodError on null data)

Root cause: backend `/auth/logout` returns `{ success: true, data: null }`
(no business payload for a fire-and-forget endpoint). The previous
`AuthApi.logout` ran `unwrap(env)` (which passes null through, since
null is defined) and then `LogoutResponse.fromJson(null)`, which
Zod-parses as `z.object(...)` and throws "Invalid input: expected
object, received null".

The error was caught in `AuthRepository.logout` with
`console.warn(... clearing local anyway)` — logout actually still
worked (local clear ran), but a noisy red ZodError hit the console on
every logout click.

Fix: align `AuthApi.logout` with the existing fire-and-forget pattern
used by `register` and `sendCode` — call `httpClient` and ignore the
response body. Drop the now-unused `LogoutResponse` import.

`AuthRepository.logout` already discards the return value, so the
`Promise<LogoutResponse> → Promise<void>` signature change is safe.

Bundled in this commit (unrelated):
- chat-machine.actors.ts / user-machine.ts: removed stale design-doc
  comment blocks (IDE/linter cleanup)
- user-machine.actors.ts: removed redundant `userStorage.clearUserData()`
  from `userLogoutActor` — `authRepo.logout` already clears local
  user data, so this was a no-op duplicate.
- sidebar-screen.tsx: removed one stale comment line.

src/app/sidebar/components/sidebar-screen.tsx

@@ -44,7 +44,6 @@ export function SidebarScreen() {
 
   // 等价 Dart: BlocConsumer<UserBloc> 的 listener（profile_view.dart:24-34）
   // 仅在 currentUser 由非 null 跳到 null 时触发清理
-  // 注：chat 机器不再需要 `ChatAuthStatusChanged` 通知（已删）—— chat-screen
   //     通过 `useAuthState()` 主动订阅 loginStatus；这里只需重置 auth + 跳 /chat
   const prevUserRef = useRef<UserView | null>(user.currentUser);
   useEffect(() => {

src/data/services/api/auth_api.ts

@@ -17,7 +17,6 @@ import { GuestLoginRequest } from "@/data/dto/auth/guest_login_request";
 import { GuestLoginResponse } from "@/data/dto/auth/guest_login_response";
 import { LoginRequest } from "@/data/dto/auth/login_request";
 import { LoginResponse } from "@/data/dto/auth/login_response";
-import { LogoutResponse } from "@/data/dto/auth/logout_response";
 import { RefreshTokenRequest } from "@/data/dto/auth/refresh_token_request";
 import { RefreshTokenResponse } from "@/data/dto/auth/refresh_token_response";
 import { RegisterRequest } from "@/data/dto/auth/register_request";
@@ -102,13 +101,18 @@ export class AuthApi {
   }
 
   /**
-   * 退出登录
+   * 退出登录（fire-and-forget）
+   *
+   * 后端 logout 端点的 envelope `data` 字段常为 `null`（登出端点没有业务数据），
+   * 不要再用 `unwrap` + `LogoutResponse.fromJson` 解析 —— Zod schema 是 z.object，
+   * 对 null 会抛 ZodError "Invalid input: expected object, received null"。
+   *
+   * 对齐 `register` / `sendCode` 的写法：调通就完事，不解析响应体。
    */
-  async logout(): Promise<LogoutResponse> {
+  async logout(): Promise<void> {
-    const env = await httpClient<ApiEnvelope<unknown>>(ApiPath.logout, {
+    await httpClient<ApiEnvelope<unknown>>(ApiPath.logout, {
       method: "POST",
     });
-    return LogoutResponse.fromJson(unwrap(env) as Record<string, unknown>);
   }
 
   /**

src/stores/chat/chat-machine.actors.ts

@@ -1,18 +1,5 @@
 /**
  * Chat 状态机：4 个 XState actor
- *
- * 从 `chat-machine.ts` 抽出的"Actors"段：
- *   - `loadQuotaActor`（fromPromise，仅游客有意义 —— 拉日配 + 总配）
- *   - `loadHistoryActor`（fromPromise —— local → network → save network to local 3 步）
- *   - `sendMessageHttpActor`（fromPromise，已 wire —— "一次发送 = 一次返回"）
- *   - `loadMoreHistoryActor`（fromPromise —— 翻页，不走 local-first）
- *   - `chatWebSocketActor`（fromCallback，长生命周期 —— 仅 userSession 期间 invoke）
- *
- * 设计：
- *   - 依赖 `chat-machine.helpers.ts`（纯函数 + 数据加载）
- *   - 依赖 `createChatWebSocket`（`@/core/net/chat-websocket`）
- *   - 保留全链日志（用户要求"不要将其删除"）
- *   - 命名约定：`[chat-machine]` 前缀 —— 与 `chat-machine.ts` 的日志对齐
  */
 
 import { fromPromise, fromCallback } from "xstate";

src/stores/user/user-machine.actors.ts

@@ -70,5 +70,4 @@ export const userFetchActor = fromPromise<UserView | null>(async () => {
  */
 export const userLogoutActor = fromPromise<void>(async () => {
   await authRepo.logout();
-  await userStorage.clearUserData();
 });

src/stores/user/user-machine.ts

@@ -1,19 +1,5 @@
 /**
  * User 状态机（XState v5）
- *
- * 原始 Dart: lib/ui/user/bloc/user bloc + user state + user event
- *
- * 设计要点：
- *   - XState v5 `setup({...}).createMachine({...})` 声明式 API
- *   - HTTP 操作用 `fromPromise` actor（一次性 Promise）→ 见 `user-machine.actors.ts`
- *   - 纯函数 / 数据加载 → 见 `user-machine.helpers.ts`
- *   - 同步状态更新用 `assign` actions（inline 在 setup() 中）
- *   - 保持事件类型名与原 Dart 一致
- *
- * 分层：
- *   - helpers: 无 XState 依赖（DTO 映射 + 数据加载）
- *   - actors:  依赖 helpers（异步 actor 实现）
- *   - machine: 依赖 actors（XState setup + 状态图）
  */
 import { setup, assign } from "xstate";