feat(iframe): add iframe bridge for ragflow integration

- Implement Penpal-based iframe communication bridge between host and child apps
- Add route handling for ragflow integration with '/route-ragflow' prefix
- Update navigation hooks to support embedded mode via iframe bridge
- Configure build and dependencies for new iframe-bridge package
- Adjust nginx config for proper SPA routing in subpath deployments

Dockerfile

@@ -50,7 +50,9 @@ server {
     # ragflow_web（Umi）部署在子路径，支持 SPA 路由
     location ${RAGFLOW_BASE} {
         alias /usr/share/nginx/html/ragflow/;
-        try_files \$uri \$uri/ /index.html;
+        # 注意：使用别名目录时，SPA 回退必须指向子路径下的 index.html
+        # 否则会错误地回退到根应用的 index.html，导致页面刷新后空白或错路由
+        try_files \$uri \$uri/ ${RAGFLOW_BASE}index.html;
     }
 
     # 静态资源缓存