Add semantic caching

tests/test_main_tool.py

@@ -28,6 +28,9 @@ class TestKnowledgeSearch:
         app.settings.deployed_index_id = "test-deployed-index"
         app.settings.search_limit = 10
 
+        # No semantic cache by default
+        app.semantic_cache = None
+
         return app
 
     @pytest.fixture