feat(website): 页脚低调展示 GitHub 累计下载量（客户端实时拉取，1h 缓存）

website/src/components/Footer.tsx

@@ -1,3 +1,4 @@
+import { useEffect, useState } from "react";
 import { recommendLinks } from "../data/recommendLinks";
 import { useLang } from "../i18n";
 import { asset } from "../lib/asset";
@@ -12,8 +13,62 @@ const logoFor: Record<string, string> = {
   "基元律动": "logos/tokenrhythm.svg",
 };
 
+// 下载统计：只拉 GitHub（公开 API 带 CORS），镜像站 Gitea 未开 CORS 不计入。
+const STATS_URL =
+  "https://api.github.com/repos/billowliu2/KimiSwitch/releases?per_page=100";
+const STATS_CACHE_KEY = "kimi-switch-downloads";
+const STATS_CACHE_TTL = 60 * 60 * 1000; // 1 hour
+
+/** GitHub Release 全部资产 download_count 之和；拉取失败返回 null（不展示）。 */
+function useDownloadCount(): number | null {
+  const [count, setCount] = useState<number | null>(null);
+  useEffect(() => {
+    let cancelled = false;
+    try {
+      const cached = localStorage.getItem(STATS_CACHE_KEY);
+      if (cached) {
+        const { ts, total } = JSON.parse(cached) as { ts: number; total: number };
+        if (Date.now() - ts < STATS_CACHE_TTL) {
+          setCount(total);
+          return;
+        }
+      }
+    } catch {
+      /* ignore corrupt cache */
+    }
+    fetch(STATS_URL)
+      .then((r) => (r.ok ? r.json() : Promise.reject(new Error(String(r.status)))))
+      .then((releases: Array<{ assets?: Array<{ download_count?: number }> }>) => {
+        if (cancelled) return;
+        const total = (releases ?? []).reduce(
+          (sum, rel) =>
+            sum +
+            (rel.assets ?? []).reduce((s, a) => s + (a.download_count ?? 0), 0),
+          0
+        );
+        setCount(total);
+        try {
+          localStorage.setItem(
+            STATS_CACHE_KEY,
+            JSON.stringify({ ts: Date.now(), total })
+          );
+        } catch {
+          /* ignore quota errors */
+        }
+      })
+      .catch(() => {
+        /* 拉取失败则不显示 */
+      });
+    return () => {
+      cancelled = true;
+    };
+  }, []);
+  return count;
+}
+
 export default function Footer() {
   const { t } = useLang();
+  const downloadCount = useDownloadCount();
   return (
     <footer className="border-t border-border py-12">
       <div className="container-page space-y-8">
@@ -100,6 +155,13 @@ export default function Footer() {
             {t.footer.creditAfter}
           </div>
         </div>
+
+        {/* 下载统计（低调展示，仅 GitHub 下载量） */}
+        {downloadCount !== null && (
+          <p className="pt-1 text-center text-xs opacity-50">
+            {t.footer.downloads.replace("{n}", downloadCount.toLocaleString())}
+          </p>
+        )}
       </div>
     </footer>
   );

website/src/i18n.tsx

@@ -345,6 +345,7 @@ const zh = {
   footer: {
     recommend: "推荐供应商",
     mirror: "国内镜像",
+    downloads: "GitHub 累计下载 {n} 次",
     creditBefore: "仪表盘与会话管理功能基于 ",
     creditAfter: " (MIT, © JochenYang) 移植",
     recommendText: {
@@ -698,6 +699,7 @@ const en: Dict = {
   footer: {
     recommend: "Recommended Providers",
     mirror: "China mirror",
+    downloads: "Total GitHub downloads: {n}",
     creditBefore: "Dashboard & session management adapted from ",
     creditAfter: " (MIT, © JochenYang)",
     recommendText: {