feat(website): 官网多页面 + 中英文切换 + Kimi 风格科技风重设计

- 多页路由：首页 / 功能 / 更新日志 / 下载（HashRouter，适配 GitHub Pages）
- 中英文切换（zh/en 双语文案 + localStorage 记忆）
- Kimi 品牌配色（中性灰 + 蓝）+ 科技风（网格底纹 / 辉光按钮 / 渐变强调词）
- 更新日志页：运行时同步 GitHub Releases，localStorage 缓存 1h，网络失败回退内置列表
- 功能页 8 张截图卡片；下载页含自动更新说明
- 修复资源路径 404（asset() + %BASE_URL%）；自托管 Inter/Fira Code 字体

website/src/hooks.ts

@@ -0,0 +1,44 @@
+import { useEffect, useRef, useState } from "react";
+
+/** Fires once when the element scrolls into view. */
+export function useInView<T extends Element = Element>(
+  options: IntersectionObserverInit = { threshold: 0.15 },
+) {
+  const ref = useRef<T | null>(null);
+  const [inView, setInView] = useState(false);
+
+  useEffect(() => {
+    const node = ref.current;
+    if (!node || inView) return;
+    const io = new IntersectionObserver(([entry]) => {
+      if (entry.isIntersecting) {
+        setInView(true);
+        io.disconnect();
+      }
+    }, options);
+    io.observe(node);
+    return () => io.disconnect();
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [inView]);
+
+  return [ref, inView] as const;
+}
+
+/** Animates a numeric value once `trigger` flips to true. */
+export function useCountUp(target: number, trigger: boolean, durationMs = 900) {
+  const [value, setValue] = useState(0);
+  useEffect(() => {
+    if (!trigger) return;
+    const start = performance.now();
+    const easeOut = (t: number) => 1 - Math.pow(1 - t, 3);
+    let raf = 0;
+    const tick = (now: number) => {
+      const p = Math.min(1, (now - start) / durationMs);
+      setValue(target * easeOut(p));
+      if (p < 1) raf = requestAnimationFrame(tick);
+    };
+    raf = requestAnimationFrame(tick);
+    return () => cancelAnimationFrame(raf);
+  }, [target, trigger, durationMs]);
+  return value;
+}