Initial backend code

package.json

@@ -0,0 +1,44 @@
+{
+  "name": "quanyixiaozhushou-backend",
+  "version": "1.0.0",
+  "description": "权益小助手后端服务 - 微信小程序后台API",
+  "main": "src/app.js",
+  "scripts": {
+    "start": "node src/app.js",
+    "dev": "nodemon src/app.js",
+    "test": "jest",
+    "lint": "eslint src/",
+    "typecheck": "tsc --noEmit"
+  },
+  "keywords": [
+    "wechat",
+    "miniprogram",
+    "equity",
+    "backend",
+    "api"
+  ],
+  "author": "",
+  "license": "MIT",
+  "dependencies": {
+    "express": "^4.18.2",
+    "cors": "^2.8.5",
+    "helmet": "^7.1.0",
+    "morgan": "^1.10.0",
+    "dotenv": "^16.3.1",
+    "mongoose": "^8.0.3",
+    "jsonwebtoken": "^9.0.2",
+    "bcryptjs": "^2.4.3",
+    "express-validator": "^7.0.1",
+    "axios": "^1.6.2",
+    "crypto-js": "^4.2.0"
+  },
+  "devDependencies": {
+    "nodemon": "^3.0.2",
+    "jest": "^29.7.0",
+    "eslint": "^8.56.0",
+    "@types/node": "^20.10.6"
+  },
+  "engines": {
+    "node": ">=18.0.0"
+  }
+}