fix: replace bare except clauses with except Exception

Bare `except:` catches BaseException including KeyboardInterrupt and
SystemExit. Replaced 4 instances with `except Exception:`.

backend/app/api/simulation.py

@@ -962,7 +962,7 @@ def get_simulation_history():
             try:
                 created_date = sim_dict.get("created_at", "")[:10]
                 sim_dict["created_date"] = created_date
-            except:
+            except Exception:
                 sim_dict["created_date"] = ""
             
             enriched_simulations.append(sim_dict)

backend/app/services/oasis_profile_generator.py

@@ -642,7 +642,7 @@ class OasisProfileGenerator:
                     result = json.loads(json_str)
                     result["_fixed"] = True
                     return result
-                except:
+                except Exception:
                     pass
         
         # 6. 尝试从内容中提取部分信息

backend/app/services/simulation_config_generator.py

@@ -520,13 +520,13 @@ class SimulationConfigGenerator:
             
             try:
                 return json.loads(json_str)
-            except:
+            except Exception:
                 # 尝试移除所有控制字符
                 json_str = re.sub(r'[\x00-\x1f\x7f-\x9f]', ' ', json_str)
                 json_str = re.sub(r'\s+', ' ', json_str)
                 try:
                     return json.loads(json_str)
-                except:
+                except Exception:
                     pass
         
         return None