feat(SimulationAPI): add function to retrieve latest report ID for a given simulation

- Implemented `_get_report_id_for_simulation` to find the most recent report ID associated with a simulation ID by scanning the reports directory.
- Updated `get_simulation_history` to include the retrieved report ID in the response, enhancing the simulation data returned to the client.

backend/app/api/simulation.py

@@ -809,6 +809,65 @@ def list_simulations():
         }), 500
 
 
+def _get_report_id_for_simulation(simulation_id: str) -> str:
+    """
+    获取 simulation 对应的最新 report_id
+    
+    遍历 reports 目录，找出 simulation_id 匹配的 report，
+    如果有多个则返回最新的（按 created_at 排序）
+    
+    Args:
+        simulation_id: 模拟ID
+        
+    Returns:
+        report_id 或 None
+    """
+    import json
+    from datetime import datetime
+    
+    # reports 目录路径：backend/uploads/reports
+    # __file__ 是 app/api/simulation.py，需要向上两级到 backend/
+    reports_dir = os.path.join(os.path.dirname(__file__), '../../uploads/reports')
+    if not os.path.exists(reports_dir):
+        return None
+    
+    matching_reports = []
+    
+    try:
+        for report_folder in os.listdir(reports_dir):
+            report_path = os.path.join(reports_dir, report_folder)
+            if not os.path.isdir(report_path):
+                continue
+            
+            meta_file = os.path.join(report_path, "meta.json")
+            if not os.path.exists(meta_file):
+                continue
+            
+            try:
+                with open(meta_file, 'r', encoding='utf-8') as f:
+                    meta = json.load(f)
+                
+                if meta.get("simulation_id") == simulation_id:
+                    matching_reports.append({
+                        "report_id": meta.get("report_id"),
+                        "created_at": meta.get("created_at", ""),
+                        "status": meta.get("status", "")
+                    })
+            except Exception:
+                continue
+        
+        if not matching_reports:
+            return None
+        
+        # 按创建时间倒序排序，返回最新的
+        matching_reports.sort(key=lambda x: x.get("created_at", ""), reverse=True)
+        return matching_reports[0].get("report_id")
+        
+    except Exception as e:
+        logger.warning(f"查找 simulation {simulation_id} 的 report 失败: {e}")
+        return None
+
+
 @simulation_bp.route('/history', methods=['GET'])
 def get_simulation_history():
     """
@@ -836,6 +895,7 @@ def get_simulation_history():
                     "updated_at": "2024-12-10",
                     "total_rounds": 120,
                     "current_round": 120,
+                    "report_id": "report_xxxx",
                     "version": "v1.0.2"
                 },
                 ...
@@ -892,6 +952,9 @@ def get_simulation_history():
             else:
                 sim_dict["files"] = []
             
+            # 获取关联的 report_id（查找该 simulation 最新的 report）
+            sim_dict["report_id"] = _get_report_id_for_simulation(sim.simulation_id)
+            
             # 添加版本号
             sim_dict["version"] = "v1.0.2"