feat: Introduce Pro subscription unlock overlay, paywall, and related account and help pages.

frontend/app/subscription-help/page.tsx

@@ -0,0 +1,113 @@
+import type { Metadata } from "next";
+import Link from "next/link";
+import {
+  ArrowLeft,
+  CheckCircle2,
+  Coins,
+  CreditCard,
+  MessageSquare,
+  ShieldCheck,
+} from "lucide-react";
+
+export const metadata: Metadata = {
+  title: "PolyWeather | 订阅说明",
+  description: "PolyWeather Pro 订阅、积分抵扣与支付方式说明。",
+};
+
+const TELEGRAM_GROUP_URL = String(
+  process.env.NEXT_PUBLIC_TELEGRAM_GROUP_URL ||
+    "https://t.me/+nMG7SjziUKYyZmM1",
+).trim();
+
+const FAQ_ITEMS = [
+  {
+    q: "Pro 包含哪些功能？",
+    a: "开通后可解锁：今日日内深度分析（含高温时段）、历史对账 + 未来日期分析、全平台智能气象推送。",
+  },
+  {
+    q: "当前订阅价格是多少？",
+    a: "目前仅提供月付：5 USDC / 30 天。",
+  },
+  {
+    q: "积分如何抵扣？",
+    a: "满 500 积分起兑，每 500 积分抵 1U，单次最多抵 3U。",
+  },
+  {
+    q: "支持哪些钱包和支付方式？",
+    a: "支持 EVM 浏览器钱包（MetaMask / OKX / Rabby / Bitget 等）及 WalletConnect 扫码钱包（Trust Wallet / Binance Web3 Wallet / TokenPocket 等）。",
+  },
+];
+
+export default function SubscriptionHelpPage() {
+  return (
+    <main className="min-h-screen bg-[#070d1d] px-4 py-10 text-slate-100">
+      <div className="mx-auto w-full max-w-4xl">
+        <Link
+          href="/account"
+          className="mb-5 inline-flex items-center gap-2 rounded-xl border border-white/10 bg-white/5 px-3 py-2 text-sm text-slate-300 transition hover:bg-white/10"
+        >
+          <ArrowLeft size={15} />
+          返回账户中心
+        </Link>
+
+        <section className="rounded-3xl border border-blue-400/20 bg-gradient-to-b from-[#162541] to-[#0e1730] p-6 md:p-8">
+          <div className="mb-5 flex items-center gap-3">
+            <ShieldCheck className="text-cyan-300" size={22} />
+            <h1 className="text-2xl font-bold md:text-3xl">PolyWeather Pro 订阅说明</h1>
+          </div>
+          <p className="text-sm text-slate-300 md:text-base">
+            这里是完整的订阅规则和支付说明。你可以先在页面内绑定钱包，再直接开通 Pro。
+          </p>
+
+          <div className="mt-6 grid gap-3 md:grid-cols-3">
+            <div className="rounded-2xl border border-white/10 bg-white/5 p-4">
+              <div className="mb-2 flex items-center gap-2 text-cyan-300">
+                <CreditCard size={16} />
+                <span className="text-sm font-semibold">订阅价格</span>
+              </div>
+              <p className="text-xl font-bold">5 USDC / 30 天</p>
+            </div>
+            <div className="rounded-2xl border border-white/10 bg-white/5 p-4">
+              <div className="mb-2 flex items-center gap-2 text-emerald-300">
+                <Coins size={16} />
+                <span className="text-sm font-semibold">积分抵扣</span>
+              </div>
+              <p className="text-xl font-bold">最多抵 3U</p>
+            </div>
+            <div className="rounded-2xl border border-white/10 bg-white/5 p-4">
+              <div className="mb-2 flex items-center gap-2 text-violet-300">
+                <MessageSquare size={16} />
+                <span className="text-sm font-semibold">社群积分</span>
+              </div>
+              <Link
+                href={TELEGRAM_GROUP_URL}
+                target="_blank"
+                className="text-sm font-semibold text-blue-300 underline decoration-blue-500/50 underline-offset-4"
+              >
+                加入社群即可赚取积分
+              </Link>
+            </div>
+          </div>
+        </section>
+
+        <section className="mt-6 rounded-3xl border border-white/10 bg-[#0f162a]/80 p-6 md:p-8">
+          <h2 className="mb-4 text-lg font-bold">常见问题</h2>
+          <div className="space-y-4">
+            {FAQ_ITEMS.map((item) => (
+              <article
+                key={item.q}
+                className="rounded-2xl border border-white/10 bg-white/[0.03] p-4"
+              >
+                <h3 className="mb-2 flex items-center gap-2 text-sm font-semibold text-blue-300">
+                  <CheckCircle2 size={14} />
+                  {item.q}
+                </h3>
+                <p className="text-sm leading-6 text-slate-300">{item.a}</p>
+              </article>
+            ))}
+          </div>
+        </section>
+      </div>
+    </main>
+  );
+}

frontend/components/account/AccountCenter.tsx

@@ -158,6 +158,11 @@ const WALLETCONNECT_POLYGON_RPC_URL = String(
   process.env.NEXT_PUBLIC_WALLETCONNECT_POLYGON_RPC_URL ||
     "https://polygon-bor-rpc.publicnode.com",
 ).trim();
+const TELEGRAM_GROUP_URL = String(
+  process.env.NEXT_PUBLIC_TELEGRAM_GROUP_URL ||
+    "https://t.me/+nMG7SjziUKYyZmM1",
+).trim();
+const SUBSCRIPTION_HELP_HREF = "/subscription-help";
 
 let walletConnectProviderCache: EvmProvider | null = null;
 let walletConnectProviderChainId: number | null = null;
@@ -1578,7 +1583,8 @@ export function AccountCenter() {
                 txHash={lastTxHash || undefined}
                 chainId={paymentConfig?.chain_id || 137}
                 paymentTokenLabel={selectedTokenLabel}
-                faqHref="/account"
+                faqHref={SUBSCRIPTION_HELP_HREF}
+                telegramGroupUrl={TELEGRAM_GROUP_URL}
               />
             </div>
           )}

frontend/components/dashboard/ProFeaturePaywall.tsx

@@ -6,6 +6,12 @@ import { useI18n } from "@/hooks/useI18n";
 import { useDashboardStore } from "@/hooks/useDashboardStore";
 import { UnlockProOverlay } from "@/components/subscription/UnlockProOverlay";
 
+const TELEGRAM_GROUP_URL = String(
+  process.env.NEXT_PUBLIC_TELEGRAM_GROUP_URL ||
+    "https://t.me/+nMG7SjziUKYyZmM1",
+).trim();
+const SUBSCRIPTION_HELP_HREF = "/subscription-help";
+
 type ProFeaturePaywallProps = {
   feature: "today" | "history" | "future";
   onClose?: () => void;
@@ -75,8 +81,8 @@ export function ProFeaturePaywall({
           router.push("/account");
         }}
         payLabel={payLabel}
-        faqHref="/account"
-        telegramGroupUrl="https://t.me/+nMG7SjziUKYyZmM1"
+        faqHref={SUBSCRIPTION_HELP_HREF}
+        telegramGroupUrl={TELEGRAM_GROUP_URL}
       />
     </div>
   );

frontend/components/subscription/UnlockProOverlay.tsx

@@ -21,6 +21,9 @@ import {
 } from "lucide-react";
 import s from "./UnlockProOverlay.module.css";
 
+const DEFAULT_FAQ_HREF = "/subscription-help";
+const DEFAULT_TELEGRAM_GROUP_URL = "https://t.me/+nMG7SjziUKYyZmM1";
+
 export type UnlockProBilling = {
   pointsEnabled: boolean;
   isEligible: boolean;
@@ -77,8 +80,8 @@ export function UnlockProOverlay({
   locale = "zh-CN",
   errorText,
   infoText,
-  faqHref = "/account",
-  telegramGroupUrl,
+  faqHref = DEFAULT_FAQ_HREF,
+  telegramGroupUrl = DEFAULT_TELEGRAM_GROUP_URL,
   txHash,
   chainId = 137,
   paymentTokenLabel,
@@ -100,6 +103,7 @@ export function UnlockProOverlay({
   const progressPct = billing.pointsEnabled
     ? Math.min(100, Math.round((points / maxPointsForFullDiscount) * 100))
     : 0;
+  const resolvedTelegramGroupUrl = String(telegramGroupUrl || "").trim();
   const txHref =
     txHash && txHash.startsWith("0x")
       ? `${chainId === 137 ? "https://polygonscan.com" : "https://etherscan.io"}/tx/${txHash}`
@@ -292,14 +296,16 @@ export function UnlockProOverlay({
             )}
 
             <div style={{ marginTop: "auto", paddingTop: 16 }}>
-              {telegramGroupUrl ? (
+              {resolvedTelegramGroupUrl ? (
                 <Link
-                  href={telegramGroupUrl}
+                  href={resolvedTelegramGroupUrl}
                   target="_blank"
                   className={s.unavailCta}
                 >
                   <MessageSquare size={12} />
-                  {isEn ? "Join Telegram to earn" : "加入电报群赚取积分"}
+                  {isEn
+                    ? "Join community to earn points"
+                    : "加入社群即可赚取积分"}
                   <ArrowRight size={11} />
                 </Link>
               ) : (