move ag-ui from tools to integrations

Author: maxkorp

docs/community/tools/ag-ui.md renamed to docs/community/integrations/ag-ui.md

@@ -158,7 +158,8 @@ nav:
       - Community Packages: community/community-packages.md
       - Tools:
         - UTCP: community/tools/utcp.md
-        - AG-UI: community/tools/ag-ui.md
+      - Integrations:
+        - AG-UI: community/integrations/ag-ui.md
       - Model Providers:
         - Cohere: community/model-providers/cohere.md
         - CLOVA Studio: community/model-providers/clova-studio.md