fix(not-found): 改 Server Component 修 Server Action 路径下 useTranslations 崩溃

爬虫向 / POST 时 Next 走 Server Action 路径，未匹配到 action 后渲染
not-found.tsx 不经过 root layout，NextIntlClientProvider 不在 React 树里，
useTranslations 抛 "No intl context" 直接 500 上报 Sentry。

改用 next-intl/server 的 getTranslations，绕开 client provider 依赖。
umami 埋点拆到 not-found-tracker.tsx 作为 client 子组件挂载。

Sentry: SENTRY-BOLE-NOTEBOOK-2

Author: github-actions[bot]

app/not-found-tracker.tsx

@@ -0,0 +1,22 @@
+"use client";
+
+import { useEffect } from "react";
+import { usePathname } from "next/navigation";
+
+// 从 not-found.tsx 拆出来的 umami 404 埋点。
+// 拆分原因：not-found.tsx 必须保持 Server Component（见同目录 not-found.tsx 注释），
+// useEffect / usePathname / window.umami 只能在 client。
+export default function NotFoundTracker() {
+  const pathname = usePathname();
+
+  useEffect(() => {
+    if (window.umami) {
+      window.umami.track("error_404", {
+        path: pathname,
+        referrer: document.referrer || "direct",
+      });
+    }
+  }, [pathname]);
+
+  return null;
+}

app/not-found.tsx

@@ -1,23 +1,14 @@
-"use client";
-
 import Link from "next/link";
-import { useEffect } from "react";
-import { usePathname } from "next/navigation";
-import { useTranslations } from "next-intl";
+import { getTranslations } from "next-intl/server";
 import { Button } from "@/app/components/ui/button";
+import NotFoundTracker from "./not-found-tracker";
 
-export default function NotFound() {
-  const pathname = usePathname();
-  const t = useTranslations("notFound");
-
-  useEffect(() => {
-    if (window.umami) {
-      window.umami.track("error_404", {
-        path: pathname,
-        referrer: document.referrer || "direct",
-      });
-    }
-  }, [pathname]);
+// 必须是 Server Component：爬虫向 / 发 POST 时 Next 走 Server Action 路径，
+// not-found 渲染不经过 layout，NextIntlClientProvider 不在树里，
+// useTranslations 会抛 "No intl context"。getTranslations 走 server，
+// 直接读 i18n/request.ts，没有 provider 依赖。
+export default async function NotFound() {
+  const t = await getTranslations("notFound");
 
   return (
     <div className="flex h-screen w-full flex-col items-center justify-center bg-background text-foreground">
@@ -32,6 +23,7 @@ export default function NotFound() {
           <Link href="/">{t("cta")}</Link>
         </Button>
       </div>
+      <NotFoundTracker />
     </div>
   );
 }