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

backend/.eslintignore

@@ -0,0 +1,20 @@
+# 构建输出
+dist/
+build/
+
+# 依赖
+node_modules/
+
+# 日志
+logs/
+*.log
+
+# 数据库
+*.db
+*.sqlite
+
+# 上传文件
+uploads/
+
+# 其他
+.DS_Store

backend/.eslintrc.js

@@ -0,0 +1,27 @@
+module.exports = {
+  root: true,
+  env: {
+    node: true,
+    es2021: true,
+    jest: true
+  },
+  extends: [
+    'eslint:recommended',
+    'plugin:prettier/recommended'
+  ],
+  parserOptions: {
+    ecmaVersion: 'latest',
+    sourceType: 'module'
+  },
+  rules: {
+    'no-unused-vars': ['error', { argsIgnorePattern: '^_', varsIgnorePattern: '^_' }],
+    'no-console': ['warn', { allow: ['warn', 'error', 'info'] }],
+    'no-undef': 'error',
+    'no-unreachable': 'error',
+    'no-unused-expressions': 'error',
+    'eqeqeq': ['error', 'always'],
+    'curly': ['error', 'all'],
+    'no-var': 'error',
+    'prefer-const': 'error'
+  }
+}

backend/.prettierrc

@@ -0,0 +1,10 @@
+{
+  "semi": true,
+  "singleQuote": true,
+  "tabWidth": 2,
+  "trailingComma": "es5",
+  "printWidth": 100,
+  "bracketSpacing": true,
+  "arrowParens": "avoid",
+  "endOfLine": "lf"
+}

backend/package.json

@@ -7,7 +7,11 @@
     "dev": "nodemon server.js",
     "create-indexes": "node create_indexes.js",
     "check-indexes": "node create_indexes.js check",
-    "drop-indexes": "node create_indexes.js drop"
+    "drop-indexes": "node create_indexes.js drop",
+    "lint": "eslint . --ext js --report-unused-disable-directives --max-warnings 0",
+    "lint:fix": "eslint . --ext js --fix",
+    "format": "prettier --write \"**/*.js\"",
+    "format:check": "prettier --check \"**/*.js\""
   },
   "dependencies": {
     "axios": "^1.13.4",
@@ -31,8 +35,15 @@
     "xlsx": "^0.18.5"
   },
   "devDependencies": {
+    "eslint": "^9.39.2",
+    "eslint-config-prettier": "^10.1.8",
+    "eslint-plugin-prettier": "^5.5.5",
+    "eslint-plugin-react": "^7.37.5",
+    "eslint-plugin-react-hooks": "^7.0.1",
+    "eslint-plugin-react-refresh": "^0.5.0",
     "jest": "^30.2.0",
     "nodemon": "^3.0.1",
+    "prettier": "^3.8.1",
     "supertest": "^7.1.4"
   }
 }