feat(workflow): enhance message stages and image routing

backend/services/brains/prompt_brain.py

@@ -33,6 +33,7 @@ from services.action_runtime import (
 )
 from services.action_stage import ActionStageRunner, ActionStageSpec, StageAction
 from services.fixed_speech import FixedSpeechOutput
+from services.message_policy import MESSAGE_CONFIRMATION
 from services.message_stage import (
     MessageDisplaySpec,
     MessageStageRunner,
@@ -271,7 +272,7 @@ class PromptBrain(BaseBrain):
                     )
                 ).strip(),
             ),
-            require_confirmation=True,
+            completion_policy=MESSAGE_CONFIRMATION,
         )
 
     async def _publish_opening_outcome(