refactor: 统一代码风格并迁移至 ESLint 新配置

style(backend): 格式化模型文件代码
style(frontend): 调整组件代码格式
chore: 删除旧 ESLint 配置并添加新配置
refactor(backend): 重构模型定义语法
style: 统一箭头函数和对象属性简写

backend/models/UserRole.js

@@ -3,16 +3,20 @@ const { sequelize } = require('../db');
 const User = require('./User');
 const Role = require('./Role');
 
-const UserRole = sequelize.define('UserRole', {
-  id: {
-    type: DataTypes.INTEGER,
-    primaryKey: true,
-    autoIncrement: true
+const UserRole = sequelize.define(
+  'UserRole',
+  {
+    id: {
+      type: DataTypes.INTEGER,
+      primaryKey: true,
+      autoIncrement: true,
+    },
+  },
+  {
+    tableName: 'user_roles',
+    timestamps: true,
   }
-}, {
-  tableName: 'user_roles',
-  timestamps: true
-});
+);
 
 UserRole.belongsTo(User, { foreignKey: 'UserId', onDelete: 'CASCADE' });
 UserRole.belongsTo(Role, { foreignKey: 'RoleId', onDelete: 'CASCADE' });