*
 * Provides shared infrastructure (HTTP client, availability checking) and
 * default implementations of RAG workflow methods with injectable prompt templates.
 * Subclasses implement provider-specific chat/streamChat and checkAvailabilityNow.
 */
public abstract class AbstractLlmClient implements LlmClient {

    private static final Logger logger = LogManager.getLogger(AbstractLlmClient.class);

                throw new LlmException("Test: no response configured");
            }
            return new LlmChatResponse(chatResponseContent);
        }

        @Override
        public void streamChat(final LlmChatRequest request, final LlmStreamCallback callback) {
            if (streamChatCapture != null) {
                streamChatCapture.capture(request, callback);
            } else {