feat(agents): implement grid/list view toggle and enhance filters

- Added grid and list view modes to AgentTypeList with user preference management.
- Enhanced filtering with category selection alongside existing search and status filters.
- Updated AgentTypeDetail with category badges and improved layout.
- Added unit tests for grid/list views and category filtering in AgentTypeList.
- Introduced `@radix-ui/react-toggle-group` for view mode toggle in AgentTypeList.

frontend/package.json

@@ -35,6 +35,7 @@
     "@radix-ui/react-separator": "^1.1.7",
     "@radix-ui/react-slot": "^1.2.4",
     "@radix-ui/react-tabs": "^1.1.13",
+    "@radix-ui/react-toggle-group": "^1.1.11",
     "@tanstack/react-query": "^5.90.5",
     "@types/react-syntax-highlighter": "^15.5.13",
     "axios": "^1.13.1",