feat(knowledge): add knowledge graph visualization component

- Add @xyflow/react dependency for graph visualization
- Create KnowledgeGraphView component with custom nodes and edges
- Extend knowledge detail hook to fetch and display graph data
- Add tabs in knowledge detail page to switch between documents and graph views

package.json

@@ -16,6 +16,7 @@
     "@mui/material": "^7.3.4",
     "@mui/x-data-grid": "^8.14.0",
     "@mui/x-date-pickers": "^8.14.0",
+    "@xyflow/react": "^12.8.6",
     "ahooks": "^3.9.5",
     "axios": "^1.12.2",
     "dayjs": "^1.11.18",