feat: 添加数据库索引优化查询性能

refactor(前端): 使用useMemo和useCallback优化性能
perf(后端): 优化统计查询性能
style: 统一前端样式定义
build: 添加创建索引脚本

backend/models/OperationLog.js

@@ -76,7 +76,14 @@ const OperationLog = sequelize.define('OperationLog', {
   tableName: 'operation_logs',
   timestamps: true,
   createdAt: 'operateTime',
-  updatedAt: false
+  updatedAt: false,
+  indexes: [
+    { fields: ['userId'] },
+    { fields: ['action'] },
+    { fields: ['module'] },
+    { fields: ['createdAt'] },
+    { fields: ['userId', 'createdAt'] }
+  ]
 });
 
 module.exports = OperationLog;