perf: streamline billing panel bootstrap

Remove the redundant billing account read, cache packages for one minute, prefetch the billing chunk, and parallelize independent package reads.

Co-Authored-By: Claude Code <noreply@anthropic.com>

frontend/src/app/(app)/page.tsx

@@ -2,6 +2,7 @@
 
 import Link from "next/link";
 import dynamic from "next/dynamic";
+import { loadBillingPanel } from "@/lib/billing-panel-loader";
 import { Sparkles } from "lucide-react";
 import { useEffect, useMemo, useRef, useState } from "react";
 import type { FormEvent, KeyboardEvent } from "react";
@@ -238,10 +239,10 @@ const BirthTimeRectification = dynamic(
     loading: () => <p className="birth-time-assistant-intent" role="status">正在加载出生时间评估...</p>,
   },
 );
-const BillingPanel = dynamic(
-  () => import("@/components/billing-panel").then((module) => module.BillingPanel),
-  { ssr: false },
-);
+const BillingPanel = dynamic(loadBillingPanel, {
+  ssr: false,
+  loading: () => <p className="secondary-page-waiting">账户信息还没拿到。</p>,
+});
 
 export default function Home() {
   const sessionList = useSessionList();

frontend/src/app/api/payment/packages/route.ts

@@ -38,20 +38,22 @@ export async function GET() {
   if (!availability.enabled)
     return NextResponse.json({ enabled: false, packages: [] });
 
-  const flags = await loadRuntimeFeatureFlags(["billing.subscriptions"]);
+  const admin = createAdminSupabaseClient();
+  const [flags, productsResult] = await Promise.all([
+    loadRuntimeFeatureFlags(["billing.subscriptions"]),
+    admin
+      .from("billing_products")
+      .select(
+        "id,code,version,name,description,product_type,billing_period,interval_count,price_cents,currency,sort_order,effective_from,effective_to",
+      )
+      .eq("enabled", true)
+      .eq("status", "published")
+      .order("sort_order")
+      .order("created_at"),
+  ]);
   const subscriptionsEnabled =
     flags.get("billing.subscriptions")?.enabled ?? false;
-
-  const admin = createAdminSupabaseClient();
-  const { data, error } = await admin
-    .from("billing_products")
-    .select(
-      "id,code,version,name,description,product_type,billing_period,interval_count,price_cents,currency,sort_order,effective_from,effective_to",
-    )
-    .eq("enabled", true)
-    .eq("status", "published")
-    .order("sort_order")
-    .order("created_at");
+  const { data, error } = productsResult;
   if (error) return NextResponse.json({ enabled: false, packages: [] });
 
   const now = Date.now();

frontend/src/components/app-sidebar.tsx

@@ -21,6 +21,8 @@ import type { Ref } from "react";
 import { AppLink } from "@/components/app-link";
 import { newChatHref, persistLoginSessionReturn, sessionHref } from "@/lib/chat-session-url";
 import { prefetchSecondaryPage } from "@/lib/secondary-page-data";
+import { prefetchBillingPanel } from "@/lib/billing-panel-loader";
+import { prefetchPaymentPackages } from "@/lib/payment-packages-cache";
 import {
   Sidebar,
   SidebarContent,
@@ -368,7 +370,12 @@ export function AppSidebar({
                   <Menu.Item className="account-menu-item" onClick={onOpenGeneral}>
                     <Settings aria-hidden="true" /><span>通用设置</span><ChevronRight aria-hidden="true" />
                   </Menu.Item>
-                  <Menu.Item className="account-menu-item" onClick={onOpenBilling}>
+                  <Menu.Item
+                    className="account-menu-item"
+                    onPointerEnter={() => { prefetchBillingPanel(); prefetchPaymentPackages(); }}
+                    onPointerDown={() => { prefetchBillingPanel(); prefetchPaymentPackages(); }}
+                    onClick={onOpenBilling}
+                  >
                     <WalletCards aria-hidden="true" /><span>账户与点数</span><small>{account.credits} 点</small>
                   </Menu.Item>
                   <Menu.Separator className="account-menu-separator" />

frontend/src/hooks/use-billing-panel.ts

@@ -10,6 +10,7 @@ import {
   type MembershipPlanAlias,
   type MembershipProduct,
 } from "@/lib/membership";
+import { fetchPaymentPackages } from "@/lib/payment-packages-cache";
 
 export type BillingAccount = {
   user: { id: string; email: string | null };
@@ -137,18 +138,14 @@ export function useBillingPanel(input: {
 
   const fetchPackages = useCallback(async () => {
     try {
-      const response = await fetch("/api/payment/packages", { cache: "no-store" });
-      const payload = await response.json().catch(() => null);
-      if (response.ok && payload?.enabled === true) {
-        setPaymentEnabled(true);
-        setPaymentPackages(payload.packages || []);
+      const payload = await fetchPaymentPackages((next) => {
+        setPaymentEnabled(next.enabled);
+        setPaymentPackages(next.packages);
         setPackagesError("");
-        return;
-      }
-      if (!response.ok) {
-        setPackagesError("套餐支付暂时不可用，请稍后重试");
-        resetPaymentState();
-      }
+      });
+      setPaymentEnabled(payload.enabled);
+      setPaymentPackages(payload.packages);
+      setPackagesError("");
     } catch {
       setPackagesError("套餐支付暂时不可用，请稍后重试");
       resetPaymentState();
@@ -181,10 +178,8 @@ export function useBillingPanel(input: {
   }, []);
 
   useEffect(() => {
-    void (async () => {
-      await Promise.allSettled([fetchAccountData(), fetchPackages()]);
-    })();
-  }, [fetchAccountData, fetchPackages]);
+    void fetchPackages();
+  }, [fetchPackages]);
 
   useEffect(() => {
     if (!input.highlightedPlan || planHighlightScrolled.current || paymentPackages.length === 0) return;

frontend/src/lib/billing-panel-loader.ts

@@ -0,0 +1,7 @@
+export function loadBillingPanel() {
+  return import("@/components/billing-panel").then((module) => module.BillingPanel);
+}
+
+export function prefetchBillingPanel(): void {
+  void loadBillingPanel();
+}

frontend/src/lib/payment-packages-cache.ts

@@ -0,0 +1,68 @@
+import type { MembershipProduct } from "./membership";
+
+export const PAYMENT_PACKAGES_CACHE_TTL_MS = 60_000;
+
+export type PaymentPackagesPayload = Readonly<{
+  enabled: boolean;
+  packages: MembershipProduct[];
+}>;
+
+type CacheEntry = Readonly<{
+  value: PaymentPackagesPayload;
+  fetchedAt: number;
+}>;
+
+let cache: CacheEntry | null = null;
+let inflight: Promise<PaymentPackagesPayload> | null = null;
+
+async function loadPaymentPackages(): Promise<PaymentPackagesPayload> {
+  const response = await fetch("/api/payment/packages", { cache: "no-store" });
+  const payload = await response.json().catch(() => null);
+  if (!response.ok || !payload || typeof payload !== "object") {
+    throw new Error("套餐支付暂时不可用，请稍后重试");
+  }
+  const record = payload as { enabled?: unknown; packages?: unknown };
+  return {
+    enabled: record.enabled === true,
+    packages: Array.isArray(record.packages) ? record.packages as MembershipProduct[] : [],
+  };
+}
+
+function refreshPaymentPackages(): Promise<PaymentPackagesPayload> {
+  if (inflight) return inflight;
+  const request = loadPaymentPackages().then((value) => {
+    cache = { value, fetchedAt: Date.now() };
+    return value;
+  }).finally(() => {
+    if (inflight === request) inflight = null;
+  });
+  inflight = request;
+  return request;
+}
+
+/**
+ * Return a fresh package response, or serve the last response while refreshing
+ * it in the background after the 60-second freshness window expires.
+ */
+export function fetchPaymentPackages(
+  onBackgroundRefresh?: (value: PaymentPackagesPayload) => void,
+): Promise<PaymentPackagesPayload> {
+  if (!cache) return refreshPaymentPackages();
+  if (Date.now() - cache.fetchedAt < PAYMENT_PACKAGES_CACHE_TTL_MS) {
+    return Promise.resolve(cache.value);
+  }
+  const request = refreshPaymentPackages();
+  void request.then((value) => onBackgroundRefresh?.(value)).catch(() => {
+    // Stale package data remains usable when a background refresh fails.
+  });
+  return Promise.resolve(cache.value);
+}
+
+export function prefetchPaymentPackages(): void {
+  void fetchPaymentPackages().catch(() => undefined);
+}
+
+export function resetPaymentPackagesCacheForTests(): void {
+  cache = null;
+  inflight = null;
+}