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/eslint.config.js

@@ -0,0 +1,70 @@
+import js from '@eslint/js';
+import globals from 'globals';
+
+export default [
+  {
+    ignores: [
+      'dist',
+      'build',
+      'node_modules',
+      'logs',
+      '*.log',
+      '*.db',
+      '*.sqlite',
+      'uploads',
+      '.DS_Store',
+    ],
+  },
+  {
+    files: ['**/*.{js,mjs,cjs}'],
+    ignores: ['tests/**'],
+    languageOptions: {
+      ecmaVersion: 'latest',
+      sourceType: 'module',
+      globals: {
+        ...globals.node,
+        ...globals.es2021,
+      },
+    },
+    plugins: {
+      '@eslint/js': js,
+    },
+    rules: {
+      ...js.configs.recommended.rules,
+      'no-unused-vars': 'off',
+      'no-console': 'off',
+      'no-undef': 'off',
+      'no-unreachable': 'off',
+      'no-unused-expressions': 'off',
+      'no-prototype-builtins': 'off',
+      'no-useless-escape': 'off',
+      'no-fallthrough': 'off',
+      eqeqeq: 'off',
+      curly: 'off',
+      'no-var': 'error',
+      'prefer-const': 'off',
+    },
+  },
+  {
+    files: ['tests/**'],
+    languageOptions: {
+      ecmaVersion: 'latest',
+      sourceType: 'module',
+      globals: {
+        ...globals.jest,
+        describe: 'readonly',
+        it: 'readonly',
+        test: 'readonly',
+        expect: 'readonly',
+        beforeAll: 'readonly',
+        afterAll: 'readonly',
+        beforeEach: 'readonly',
+        afterEach: 'readonly',
+      },
+    },
+    rules: {
+      'no-undef': 'off',
+      'no-unused-vars': 'off',
+    },
+  },
+];