feat: 实现联系表单提交与邮件通知功能

添加联系表单提交接口和邮件通知功能，支持从环境变量读取 SMTP 配置
重构 SEO 配置到 site.json，新增 robots.txt 和 sitemap.xml 生成
更新公司电话并添加 PM2 生产运行配置

package.json

@@ -10,7 +10,6 @@
   },
   "dependencies": {
     "@hookform/resolvers": "^3.9.1",
-    "@vercel/analytics": "1.6.1",
     "@radix-ui/react-accordion": "1.2.12",
     "@radix-ui/react-alert-dialog": "1.1.15",
     "@radix-ui/react-aspect-ratio": "1.1.8",
@@ -38,6 +37,7 @@
     "@radix-ui/react-toggle": "1.1.10",
     "@radix-ui/react-toggle-group": "1.1.11",
     "@radix-ui/react-tooltip": "1.2.8",
+    "@vercel/analytics": "1.6.1",
     "autoprefixer": "^10.4.20",
     "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.1",
@@ -48,6 +48,7 @@
     "lucide-react": "^0.564.0",
     "next": "16.1.6",
     "next-themes": "^0.4.6",
+    "nodemailer": "^8.0.2",
     "react": "19.2.4",
     "react-day-picker": "9.13.2",
     "react-dom": "19.2.4",
@@ -57,11 +58,13 @@
     "sonner": "^1.7.1",
     "tailwind-merge": "^3.3.1",
     "vaul": "^1.1.2",
+    "yaml": "^2.8.2",
     "zod": "^3.24.1"
   },
   "devDependencies": {
     "@tailwindcss/postcss": "^4.2.0",
     "@types/node": "^22",
+    "@types/nodemailer": "^7.0.11",
     "@types/react": "19.2.14",
     "@types/react-dom": "19.2.3",
     "postcss": "^8.5",