refactor(auth): centralize auth routing via proxy and marker cookie

src/app/api/auth/marker/route.ts

@@ -0,0 +1,51 @@
+/**
+ * 路由信号 cookie 管理端点
+ *
+ * 用途：写/清 `cozsweet_authed` httpOnly cookie，作为 `src/router/proxy.ts`
+ * 的"用户已登录"信号源。
+ *
+ * 与 `next-auth.session-token` 的区别：
+ *   - NextAuth cookie 仅社交登录设置，邮箱登录不写入
+ *   - 本端点由所有登录出口（社交 / 邮箱）统一调用，proxy 只需读这一个 cookie
+ *
+ * 调用方：
+ *   - 社交登录出口（nextauth-helpers.persistBackendSession，**server 端**直接用
+ *     `next/headers.cookies()` 写，不走本端点）
+ *   - 邮箱登录出口（auth-machine.emailLoginActor / emailRegisterThenLoginActor，
+ *     **client 端** fetch POST）
+ *   - 登出（nextauth-helpers.logout，client 端 fetch DELETE）
+ *
+ * 安全：cookie 设为 `HttpOnly` + `SameSite=Lax`，prod 额外 `Secure`。
+ */
+
+import { NextResponse } from "next/server";
+
+const COOKIE_NAME = "cozsweet_authed";
+const ONE_WEEK = 60 * 60 * 24 * 7;
+
+/** 设置 httpOnly 路由信号 cookie（任何登录成功后调用） */
+export async function POST() {
+  const res = NextResponse.json({ ok: true });
+  res.cookies.set({
+    name: COOKIE_NAME,
+    value: "1",
+    httpOnly: true,
+    secure: process.env.NODE_ENV === "production",
+    sameSite: "lax",
+    path: "/",
+    maxAge: ONE_WEEK,
+  });
+  return res;
+}
+
+/** 清除路由信号 cookie（登出时调用） */
+export async function DELETE() {
+  const res = NextResponse.json({ ok: true });
+  res.cookies.set({
+    name: COOKIE_NAME,
+    value: "",
+    path: "/",
+    maxAge: 0,
+  });
+  return res;
+}

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

@@ -13,10 +13,9 @@
 import { useEffect, useRef } from "react";
 import { useRouter } from "next/navigation";
 
-import { useAuthState, useAuthDispatch } from "@/stores/auth/auth-context";
+import { useAuthState } from "@/stores/auth/auth-context";
 import { useChatDispatch } from "@/stores/chat/chat-context";
 import { useUserDispatch } from "@/stores/user/user-context";
-import { useAuthGate } from "@/lib/auth/nextauth";
 import { ROUTES } from "@/router/routes";
 import { MobileShell } from "@/app/_components/core/mobile-shell";
 import { AuthPanel } from "@/app/auth/components/auth-panel";
@@ -29,19 +28,17 @@ export interface AuthScreenProps {
 export function AuthScreen({
   background = "var(--color-sidebar-background)",
 }: AuthScreenProps) {
+  // ===== 鉴权路由跳转已由 src/router/proxy.ts 集中处理 =====
+  // 本组件只负责：
+  //   1. 渲染登录面板
+  //   2. 登录成功后初始化 chat/user store + navigate 到 /chat（业务层动作）
+
   const router = useRouter();
-  const { isAuthed } = useAuthGate();
   const state = useAuthState();
-  const authDispatch = useAuthDispatch();
   const chatDispatch = useChatDispatch();
   const userDispatch = useUserDispatch();
   const wasSuccess = useRef(false);
 
-  // 已登录 → 自动跳 /chat
-  useEffect(() => {
-    if (isAuthed) router.replace(ROUTES.chat);
-  }, [isAuthed, router]);
-
   // 邮箱登录成功 → 通知 Chat + User + 跳转
   useEffect(() => {
     if (state.isSuccess && !wasSuccess.current) {

src/app/splash/components/splash-button.tsx

@@ -17,10 +17,10 @@ import Link from "next/link";
 import { useRouter } from "next/navigation";
 import { useEffect, useRef } from "react";
 
-import { useAuthState, useAuthDispatch } from "@/stores/auth/auth-context";
+import { useAuthState } from "@/stores/auth/auth-context";
 import { useChatDispatch } from "@/stores/chat/chat-context";
 import { useUserDispatch } from "@/stores/user/user-context";
-import { facebookLogin, useAuthGate } from "@/lib/auth/nextauth";
+import { facebookLogin } from "@/lib/auth/nextauth";
 import { ROUTES } from "@/router/routes";
 import { LoadingIndicator } from "@/app/_components/core/loading-indicator";
 import styles from "./splash-button.module.css";
@@ -31,10 +31,13 @@ export interface SplashButtonProps {
 }
 
 export function SplashButton({ skipHref = ROUTES.chat }: SplashButtonProps) {
-  // ===== 鉴权状态 =====
-  const { isAuthed } = useAuthGate();
+  // ===== 鉴权路由跳转已由 src/router/proxy.ts 集中处理 =====
+  // 本组件只负责：
+  //   1. 触发登录动作
+  //   2. 登录成功后初始化 chat/user store + navigate 到 /chat（业务层动作，
+  //      不是鉴权判断；proxy 会让通过因为 cookie 已设）
+
   const state = useAuthState();
-  const authDispatch = useAuthDispatch();
   const isLoading = state.isLoading;
 
   // ===== 跨 store 初始化（登录成功后触发） =====
@@ -43,11 +46,6 @@ export function SplashButton({ skipHref = ROUTES.chat }: SplashButtonProps) {
   const router = useRouter();
   const wasSuccess = useRef(false);
 
-  // 已登录时跳 /chat
-  useEffect(() => {
-    if (isAuthed) router.replace(ROUTES.chat);
-  }, [isAuthed, router]);
-
   // 邮箱登录成功跳 /chat + 通知 chat/user 初始化
   useEffect(() => {
     if (state.isSuccess && !wasSuccess.current) {