feat(site): 官网全新重建（App 真相源风格）+ 四档套餐 + 在线购买流

- tokens.css/site.css 逐值对齐原型设计系统，icons 雪碧图，零外链；首页/下载/帮助/法务全站重皮肤，真实截图
- 注册与登录在官网内完成（写 shared_preferences_web 兼容 localStorage，不再跳 App）
- 价格区四档：免费/标准 299/高级 599/定制；登录后标准/高级按钮变「购买 / 续费」
- 新增 /checkout/（套餐+月付年付切换）与 /license/result/（支付回跳轮询到账）
- 登录页支持 ?next= 站内回跳；二维码措辞改「扫码看详情可分享」
- 下载页构建期真实下载链接+运行时 release 刷新；旧 features 页/死 CSS/dist 产物清理

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JJ1g8XV1YhhmHRzhwWEW7o

web/_includes/nav.njk

@@ -1,34 +1,31 @@
-<nav class="topnav">
-  <div class="topnav-inner">
-    <a href="/" class="topnav-brand">
-      <img src="/assets/logo-full.svg" alt="岩美" />
+<nav class="nav">
+  <div class="nav-in">
+    <a class="nav-logo" href="/">
+      <img src="/assets/logo-mark.svg" alt="{{ site.name }}" />
+      岩美酒库
     </a>
-    <div class="topnav-links">
+    <div class="nav-links">
       <a href="/#modules">产品</a>
-      <a href="/features/inventory.html">库存</a>
-      <a href="/features/approval.html">审核流</a>
+      <a href="/#workflow">审核流</a>
       <a href="/#pricing">价格</a>
       <a href="/download/">下载</a>
-      <a href="/docs/">文档</a>
-      <a href="/#faq">支持</a>
+      <a href="/docs/">帮助</a>
     </div>
-    <div class="topnav-cta" id="nav-cta">
-      <a href="/register/" class="btn btn-primary btn-sm">注册门店</a>
+    <div class="nav-cta" id="nav-cta">
+      <a class="btn ghost" href="/login/">登录</a>
+      <a class="btn primary" href="/register/">注册门店</a>
     </div>
-    <button class="nav-hamburger" id="nav-hamburger" aria-label="菜单" aria-expanded="false">
-      <span></span><span></span><span></span>
+    <button class="nav-burger" id="nav-burger" aria-label="菜单" aria-expanded="false">
+      <svg class="ic" style="width:22px;height:22px"><use href="#i-menu"/></svg>
     </button>
   </div>
-  <div class="nav-mobile-menu" id="nav-mobile-menu">
+  <div class="nav-mobile" id="nav-mobile-menu">
     <a href="/#modules">产品</a>
-    <a href="/features/inventory.html">库存管理</a>
-    <a href="/features/approval.html">审核流</a>
+    <a href="/#workflow">审核流</a>
     <a href="/#pricing">价格</a>
     <a href="/download/">下载</a>
-    <a href="/docs/">文档</a>
-    <a href="/#faq">支持</a>
-    <div class="nav-mobile-cta" id="nav-mobile-cta">
-      <a href="/register/" class="btn btn-primary">注册门店</a>
-    </div>
+    <a href="/docs/">帮助</a>
+    <a href="/register/">注册门店</a>
+    <a href="/login/">登录</a>
   </div>
 </nav>