后台数据可视化：Recharts 漏斗图、总览页 KPI 卡片和缓存饼图

frontend/app/ops/overview/page.tsx

@@ -0,0 +1,10 @@
+import type { Metadata } from "next";
+import { requireOpsAdmin } from "@/lib/ops-admin";
+import { OverviewPageClient } from "@/components/ops/overview/OverviewPageClient";
+
+export const metadata: Metadata = { title: "总览 — PolyWeather Ops" };
+
+export default async function OverviewPage() {
+  await requireOpsAdmin("/ops/overview");
+  return <OverviewPageClient />;
+}

frontend/app/ops/page.tsx

@@ -1,5 +1,5 @@
 import { redirect } from "next/navigation";
 
 export default function OpsPage() {
-  redirect("/ops/system");
+  redirect("/ops/overview");
 }