Add V2 external service providers

ai_knowledge_base_v2/apps/backend/.env.example

@@ -14,6 +14,11 @@ MOCK_SMS_ENABLED=true
 MOCK_SMS_CODE=123456
 SMS_CODE_EXPIRE_MINUTES=5
 MOCK_RAG_ENABLED=true
+MOCK_MODEL_ENABLED=true
+FEISHU_MOCK_ENABLED=true
+FEISHU_SEARCH_URL=
+FEISHU_TIMEOUT_SECONDS=20
+FEISHU_RETRY_COUNT=2
 
 DEFAULT_DAILY_CHAT_LIMIT=100
 DEFAULT_USER_NAME_PREFIX=用户