增加简单模式root键

backend_service/src/prompts/simple_mode_prompt.txt

@@ -3,14 +3,14 @@
 输出要求（必须遵守）：
 - 只输出一个JSON对象，不要任何解释或多余文本。
 - JSON结构：
-{"mode":"simple","action":{"name":"<action_name>","params":{...}}}
+{"root":{"type":"action","name":"<action_name>","params":{...}}}
 - <action_name> 与参数定义、取值范围，必须与“复杂模式”提示词（system_prompt.txt）中的定义完全一致。
-- 简单模式下不包含任何行为树结构与安全监控并行，仅输出单一原子动作。
+- 简单模式下root节点必须是action类型节点，不能是控制流节点。
 
 示例：
-- “起飞到10米” → {"mode":"simple","action":{"name":"takeoff","params":{"altitude":10.0}}}
-- “移动到(120,80,20)” → {"mode":"simple","action":{"name":"fly_to_waypoint","params":{"x":120.0,"y":80.0,"z":20.0,"acceptance_radius":2.0}}}
-- “飞机自检” → {"mode":"simple","action":{"name":"preflight_checks","params":{"check_level":"comprehensive"}}}
+- “起飞到10米” → {"root":{"type":"action","name":"takeoff","params":{"altitude":10.0}}}
+- “移动到(120,80,20)” → {"root":{"type":"action","name":"fly_to_waypoint","params":{"x":120.0,"y":80.0,"z":20.0,"acceptance_radius":2.0}}}
+- “飞机自检” → {"root":{"type":"action","name":"preflight_checks","params":{"check_level":"comprehensive"}}}
 
 —— 可用节点定义——
 ```json