refactor: strengthen architecture CI gates and runtime contracts

app/api/dependencies/agent.py

@@ -4,15 +4,15 @@ from fastapi import Depends
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from app.api.context import (
-    get_agent_chat_runtime,
     get_agent_chat_repository,
+    get_agent_chat_runtime,
     get_agent_chat_transaction,
     get_async_session,
     get_host_runtime,
 )
 from app.application.messaging.chat import (
-    AgentChatService,
     AgentChatPersistenceService,
+    AgentChatService,
     AsyncAgentChatRepository,
     AsyncUnitOfWork,
 )