fix: 去除LLM直接生成图片占位符逻辑

api/app/agents/memoir/narrative_agent.py

@@ -10,7 +10,7 @@ from app.core.logging import get_logger
 
 from app.agents.memoir.prompts import (
     get_creative_title_prompt,
-    get_narrative_prompt,
+    get_narrative_json_prompt,
 )
 
 logger = get_logger(__name__)
@@ -61,7 +61,7 @@ class NarrativeAgent:
                 return f"{existing_content}\n\n{new_content}"
             return new_content
         try:
-            prompt = get_narrative_prompt(
+            prompt = get_narrative_json_prompt(
                 stage=stage,
                 slots=slots,
                 new_content=new_content,