refactor(app): tighten chat and sync boundaries

src/stores/user/index.ts

@@ -2,7 +2,6 @@
  * @file Automatically generated by barrelsby.
  */
 
-export * from "./user-auth-sync";
 export * from "./user-context";
 export * from "./user-events";
 export * from "./user-machine.actors";

src/stores/user/user-auth-sync.tsx

@@ -1,39 +0,0 @@
-"use client";
-
-/**
- * Auth → User 同步器
- *
- * AuthStatusChecker 只负责恢复 loginStatus；用户资料由 user machine
- * 管理。这里持续监听登录态变化：
- *   - notLoggedIn → 清空本地 user context
- *   - guest / email / OAuth → 重新 hydrate user store
- */
-import { useEffect, useRef } from "react";
-
-import type { LoginStatus } from "@/data/dto/auth";
-import { useAuthState } from "@/stores/auth/auth-context";
-
-import { useUserDispatch } from "./user-context";
-
-export function UserAuthSync() {
-  const { hasInitialized, isLoading, loginStatus } = useAuthState();
-  const userDispatch = useUserDispatch();
-  const prevLoginStatusRef = useRef<LoginStatus | null>(null);
-
-  useEffect(() => {
-    if (!hasInitialized || isLoading) return;
-
-    const prev = prevLoginStatusRef.current;
-    if (prev === loginStatus) return;
-    prevLoginStatusRef.current = loginStatus;
-
-    if (loginStatus === "notLoggedIn") {
-      userDispatch({ type: "UserClearLocal" });
-      return;
-    }
-
-    userDispatch({ type: "UserInit" });
-  }, [hasInitialized, isLoading, loginStatus, userDispatch]);
-
-  return null;
-}