feat: add AI agent optimization and WeChat ID to website

- Add JSON-LD structured data for AI crawlers and search engines
- Add llms.txt for AI agent discovery (product info, commands, skills)
- Add WeChat ID (hecare888) to contact section in help doc
- Add canonical URL and robots meta

website/index.html

@@ -9,7 +9,41 @@
     <meta property="og:description" content="Like YuLinMuFeng for AI. Plug in USB, double-click, done. 插上U盘，双击运行，搞定。">
     <meta property="og:type" content="website">
     <meta property="og:url" content="https://u-claw.org">
+    <meta name="robots" content="index, follow">
+    <link rel="canonical" href="https://u-claw.org">
     <link rel="icon" href="data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 100 100'><text y='.9em' font-size='90'>🦞</text></svg>">
+    <script type="application/ld+json">
+    {
+      "@context": "https://schema.org",
+      "@type": "SoftwareApplication",
+      "name": "U-Claw 虾盘",
+      "alternateName": "U-Claw",
+      "description": "OpenClaw AI 助手离线安装 U 盘。专为中国用户打造，免翻墙一键安装。内置 52 个技能、8 大国产模型、QQ/飞书/钉钉/企微多平台接入。",
+      "url": "https://u-claw.org",
+      "applicationCategory": "DeveloperApplication",
+      "operatingSystem": "macOS, Windows, Linux",
+      "softwareVersion": "1.1",
+      "license": "https://opensource.org/licenses/MIT",
+      "offers": { "@type": "Offer", "price": "0", "priceCurrency": "CNY" },
+      "author": {
+        "@type": "Person",
+        "name": "dongsheng",
+        "url": "https://github.com/dongsheng123132",
+        "email": "hefangsheng@gmail.com"
+      },
+      "codeRepository": "https://github.com/dongsheng123132/u-claw",
+      "keywords": ["OpenClaw", "AI助手", "离线安装", "U盘", "中国", "DeepSeek", "QQ机器人", "飞书", "钉钉", "免翻墙"],
+      "featureList": [
+        "完全离线安装，无需翻墙",
+        "支持 macOS / Windows / Linux",
+        "8 大国产模型：DeepSeek、Kimi、通义千问、智谱GLM、MiniMax、豆包、千帆、Mimo",
+        "QQ / 飞书 / 钉钉 / 企业微信 / Telegram / Discord 多平台接入",
+        "52 个预装技能",
+        "便携模式：插上 U 盘即用，配置跟着 U 盘走",
+        "安装到电脑：一键永久安装"
+      ]
+    }
+    </script>
     <style>
         * { margin: 0; padding: 0; box-sizing: border-box; }
         :root {