feat: add SharePanel component for social sharing with QR code support

- Implemented SharePanel component in `SharePanel.astro` for sharing content on social media platforms.
- Integrated QR code generation for WeChat sharing using the `qrcode` library.
- Added localization support for English and Chinese languages.
- Created utility functions in `seo.ts` for building article summaries and FAQs.
- Introduced API routes for serving IndexNow key and generating full LLM catalog and summaries.
- Enhanced SEO capabilities with structured data for articles and pages.

frontend/README.md

@@ -58,3 +58,27 @@ admin 侧上传封面时也会额外做：
 - 上传前压缩
 - 16:9 封面规范化
 - 优先转为 `AVIF / WebP`
+
+## GEO / AI 搜索补充
+
+前台现在额外提供：
+
+- `/llms.txt`
+- `/llms-full.txt`
+- `/indexnow-key.txt`（仅在配置 `INDEXNOW_KEY` 时可用）
+
+如果你想在发布后主动推送 IndexNow，可以配置：
+
+```env
+INDEXNOW_KEY=your-indexnow-key
+SITE_URL=https://your-frontend.example.com
+PUBLIC_API_BASE_URL=https://your-frontend.example.com/api
+```
+
+然后运行：
+
+```powershell
+pnpm indexnow:submit
+```
+
+脚本会自动收集首页、文章、分类、标签、评测等 canonical URL 并提交到 IndexNow。