chore: 统一代码风格并配置ESLint和Prettier

配置ESLint和Prettier规则
添加前端和后端的忽略文件
统一代码格式和缩进
修复代码风格问题

frontend/.eslintrc.cjs

@@ -0,0 +1,26 @@
+module.exports = {
+  root: true,
+  env: { browser: true, es2020: true },
+  extends: [
+    'eslint:recommended',
+    'plugin:react/recommended',
+    'plugin:react/jsx-runtime',
+    'plugin:react-hooks/recommended',
+    'plugin:prettier/recommended'
+  ],
+  ignorePatterns: ['dist', '.eslintrc.cjs'],
+  parserOptions: { ecmaVersion: 'latest', sourceType: 'module' },
+  settings: { react: { version: '18.2' } },
+  plugins: ['react-refresh'],
+  rules: {
+    'react/jsx-no-target-blank': 'off',
+    'react-refresh/only-export-components': [
+      'warn',
+      { allowConstantExport: true }
+    ],
+    'no-unused-vars': ['error', { argsIgnorePattern: '^_', varsIgnorePattern: '^_' }],
+    'no-console': ['warn', { allow: ['warn', 'error'] }],
+    'react/prop-types': 'off',
+    'react/display-name': 'off'
+  }
+}