fix(nav): 非首页点击 Header 也能回主页

- BrandMark 外层包 <Link href="/">，点 logo 回首页
- Header 三个锚点从 #features 改为 /#features 等绝对路径，
  从 /rank 或任意子页点导航能跳回主页对应区块

方案 F（最小修复），比引入 Header 全站 layout 或新组件成本更低。

Author: longsizhuo

app/components/BrandMark.tsx

@@ -12,6 +12,7 @@
  * @param {boolean} priority - 是否优先加载
  */
 import Image from "next/image";
+import Link from "next/link";
 import { cn } from "@/lib/utils";
 
 export const BRAND_NAME = "Involution Hell";
@@ -38,7 +39,7 @@ export function BrandMark({
   const width = Math.round(imageSize * BRAND_LOGO_ASPECT_RATIO);
 
   return (
-    <div className={cn("flex items-center gap-2", className)}>
+    <Link href="/" className={cn("flex items-center gap-2", className)}>
       <div className="relative">
         <Image
           src={BRAND_LOGO_LIGHT_SRC}
@@ -65,6 +66,6 @@ export function BrandMark({
       >
         {BRAND_NAME}
       </span>
-    </div>
+    </Link>
   );
 }

app/components/Header.tsx

@@ -31,7 +31,16 @@ export function Header() {
         <div className="flex items-center justify-between h-10">
           <nav className="hidden md:flex items-center gap-8 font-sans text-xs font-bold uppercase tracking-widest text-[var(--foreground)]">
             <a
-              href="#features"
+              href="/"
+              className="hover:text-[#CC0000] transition-colors"
+              data-umami-event="navigation_click"
+              data-umami-event-region="header"
+              data-umami-event-label="home"
+            >
+              首页
+            </a>
+            <a
+              href="/#features"
               className="hover:text-[#CC0000] transition-colors"
               data-umami-event="navigation_click"
               data-umami-event-region="header"
@@ -40,7 +49,7 @@ export function Header() {
               特点
             </a>
             <a
-              href="#community"
+              href="/#community"
               className="hover:text-[#CC0000] transition-colors"
               data-umami-event="navigation_click"
               data-umami-event-region="header"
@@ -49,7 +58,7 @@ export function Header() {
               社区
             </a>
             <a
-              href="#contact"
+              href="/#contact"
               className="hover:text-[#CC0000] transition-colors"
               data-umami-event="navigation_click"
               data-umami-event-region="header"