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

tsconfig.json

@@ -2,7 +2,8 @@
   "files": [],
   "references": [
     { "path": "./tsconfig.app.json" },
-    { "path": "./tsconfig.node.json" }
+    { "path": "./tsconfig.node.json" },
+    { "path": "./packages/iframe-bridge/tsconfig.json" }
   ],
   // exclude rag_web_core/**/*
   "exclude": [