Enhance interview prompt handling and update README.md

- Introduced a prefix to optimize interview prompts, ensuring agents respond directly with text without invoking tools.
- Updated the simulation API to utilize the optimized prompts for individual and batch interviews.
- Modified the `get_interview_history` function to allow for flexible platform querying, returning results from both Reddit and Twitter when no platform is specified.
- Enhanced README.md to include new prompt optimization details and updated API usage examples for clarity.

backend/app/services/simulation_runner.py

@@ -1279,30 +1279,16 @@ class SimulationRunner:
             }
     
     @classmethod
-    def get_interview_history(
+    def _get_interview_history_from_db(
         cls,
-        simulation_id: str,
-        platform: str = "reddit",
+        db_path: str,
+        platform_name: str,
         agent_id: Optional[int] = None,
         limit: int = 100
     ) -> List[Dict[str, Any]]:
-        """
-        获取Interview历史记录（从数据库读取）
-        
-        Args:
-            simulation_id: 模拟ID
-            platform: 平台类型（reddit/twitter）
-            agent_id: 过滤Agent ID（可选）
-            limit: 返回数量限制
-            
-        Returns:
-            Interview历史记录列表
-        """
+        """从单个数据库获取Interview历史"""
         import sqlite3
         
-        sim_dir = os.path.join(cls.RUN_STATE_DIR, simulation_id)
-        db_path = os.path.join(sim_dir, f"{platform}_simulation.db")
-        
         if not os.path.exists(db_path):
             return []
         
@@ -1312,8 +1298,6 @@ class SimulationRunner:
             conn = sqlite3.connect(db_path)
             cursor = conn.cursor()
             
-            # 构建查询
-            # 注意：ActionType.INTERVIEW.value 应该是字符串形式
             if agent_id is not None:
                 cursor.execute("""
                     SELECT user_id, info, created_at
@@ -1342,13 +1326,66 @@ class SimulationRunner:
                     "response": info.get("response", info),
                     "prompt": info.get("prompt", ""),
                     "timestamp": created_at,
-                    "platform": platform
+                    "platform": platform_name
                 })
             
             conn.close()
             
         except Exception as e:
-            logger.error(f"读取Interview历史失败: {e}")
+            logger.error(f"读取Interview历史失败 ({platform_name}): {e}")
+        
+        return results
+
+    @classmethod
+    def get_interview_history(
+        cls,
+        simulation_id: str,
+        platform: str = None,
+        agent_id: Optional[int] = None,
+        limit: int = 100
+    ) -> List[Dict[str, Any]]:
+        """
+        获取Interview历史记录（从数据库读取）
+        
+        Args:
+            simulation_id: 模拟ID
+            platform: 平台类型（reddit/twitter/None）
+                - "reddit": 只获取Reddit平台的历史
+                - "twitter": 只获取Twitter平台的历史
+                - None: 获取两个平台的所有历史
+            agent_id: 指定Agent ID（可选，只获取该Agent的历史）
+            limit: 每个平台返回数量限制
+            
+        Returns:
+            Interview历史记录列表
+        """
+        sim_dir = os.path.join(cls.RUN_STATE_DIR, simulation_id)
+        
+        results = []
+        
+        # 确定要查询的平台
+        if platform in ("reddit", "twitter"):
+            platforms = [platform]
+        else:
+            # 不指定platform时，查询两个平台
+            platforms = ["twitter", "reddit"]
+        
+        for p in platforms:
+            db_path = os.path.join(sim_dir, f"{p}_simulation.db")
+            platform_results = cls._get_interview_history_from_db(
+                db_path=db_path,
+                platform_name=p,
+                agent_id=agent_id,
+                limit=limit
+            )
+            results.extend(platform_results)
+        
+        # 按时间降序排序
+        results.sort(key=lambda x: x.get("timestamp", ""), reverse=True)
+        
+        # 如果查询了多个平台，限制总数
+        if len(platforms) > 1 and len(results) > limit:
+            results = results[:limit]
         
         return results