Add fake llm provider

Change-Id: I7983796013f27e146506a42c8238b69a1838f1d9
diff --git a/server/agent/manager.go b/server/agent/manager.go
index 2d31b87..74e6771 100644
--- a/server/agent/manager.go
+++ b/server/agent/manager.go
@@ -87,7 +87,7 @@
 
 	// Create LLM provider
 	llmConfig := llm.Config{
-		Provider: llm.ProviderOpenAI,
+		Provider: llm.ProviderFake, // Use fake provider for testing
 		APIKey:   m.config.OpenAI.APIKey,
 		BaseURL:  m.config.OpenAI.BaseURL,
 		Timeout:  m.config.OpenAI.Timeout,