refactor: 清理代码质量和移除未使用文件

- 移除未使用的导入语句和变量
- 修复代码风格问题（空格、格式化等）
- 删除备份文件和测试文件
- 改进异常处理链式调用
- 添加权限系统数据库模型和配置
- 更新版本号至6.4.4
- 优化SQL查询使用正确的布尔表达式

src/chat/memory_system/action_diagnostics.py

@@ -214,7 +214,7 @@ class ActionDiagnostics:
                 raise Exception("注册失败")
                 
         except Exception as e:
-            raise Exception(f"手动注册no_reply Action失败: {e}")
+            raise Exception(f"手动注册no_reply Action失败: {e}") from e
     
     def run_full_diagnosis(self) -> Dict[str, Any]:
         """运行完整诊断"""

src/chat/memory_system/async_memory_optimizer.py

@@ -131,7 +131,7 @@ class AsyncMemoryQueue:
                         await task.callback(None)
                     else:
                         task.callback(None)
-                except:
+                except Exception:
                     pass
     
     async def _handle_store_task(self, task: MemoryTask) -> Any:

src/chat/memory_system/vector_instant_memory.py

@@ -271,7 +271,7 @@ class VectorInstantMemoryV2:
                 return f"{int(diff/3600)}小时前"
             else:
                 return f"{int(diff/86400)}天前"
-        except:
+        except Exception:
             return "时间格式错误"
     
     async def get_memory_for_context(self, current_message: str, context_size: int = 3) -> str:
@@ -318,7 +318,7 @@ class VectorInstantMemoryV2:
             try:
                 result = self.collection.count()
                 stats["total_messages"] = result
-            except:
+            except Exception:
                 stats["total_messages"] = "查询失败"
         
         return stats