Update llm.yml

Author: alabulei1

.claude/skills/echokit-config-generator/platforms/llm.yml

@@ -11,7 +11,7 @@ openai_chat:
 
 openai_response:
   name: "OpenAI Responses API"
-  platform: "openai_response"
+  platform: "openai_responses"
   url: "https://api.openai.com/v1/responses"
   model: "gpt-4o-mini"
   history: 5